PIO - When using this mode, reading data from disk is controlled by the CPU, which leads to increased load on the CPU and slowdown in general.

The ATA 2 / EIDE and ATA 3 standards provide several modes for fast data exchange with hard drives. The description of these modes is an essential part of the standard, which owes its appearance in many respects to these new capabilities. Most modern high-speed hard drives can operate in the so-called PIO 3 and PIO 4 modes, in which the data exchange rate is very high. The choice of PIO (Programmable I / O) mode determines the speed of data exchange with the hard disk. In the slowest mode (mode 0), the duration of one data transmission cycle does not exceed 600 ns. Each cycle transfers 16 bits of data, so the theoretical baud rate in mode 0 is 3.3 MB / s. Most modern hard drives support PIO 4 mode, in which the data transfer rate reaches 16.6 MB / s.

Parallel ATA DMA Communication Modes

DMA - the drive itself manages the data flow, reading data into or from memory with almost no CPU involvement. The CPU issues commands to perform an action.

Direct memory access (DMA) transfer means that, unlike PIO mode, data is transferred directly from the hard disk to system (main) memory, bypassing the CPU. This frees the processor from most of the disk data exchange operations. In addition, the processor can perform other useful work while transferring data from disk to memory. There are two types of direct memory access: single-word (8-bit) and verbose (16-bit). The one-word DMA modes have been removed from the ATA 3 standard as well as from later specifications and are not currently used. DMA modes using a host adapter that supports bus control technology are called Bus Master ATA modes. In the first case, request processing, bus capture, and data transfer are handled by the DMA controller on the motherboard. In the second case, all these operations are performed by an additional high-speed microcircuit, also mounted on the motherboard.

1. PCI bus development. PCI devices

Local PCI bus

The PCI (Peripheral Component Interaction) bus was announced by Intel in 1992 at the PC Expo.

• 32-bit data channel between the processor and peripheral devices
• runs at a clock frequency of 33 MHz
• Maximum throughput 120 MB / s

When working with i486 processors, the PCI bus gives approximately the same performance indicators as the VL-bus.

The PCI bus is processor-independent (the VL-bus is connected directly to the i486 processor).

PCI runs at 66 MHz.

32 bit - at 33 MHz (132 MB / s).

64 bit - at 33 MHz (264 MB / s), about 66 MHz (528 MB / s).

Connected devices: audio cards, network cards, video cards.

You can connect cards to the PCI bus connector: with power supply of 5 V (key 50, 51 pins), 3.3V (key 12,13) \u200b\u200band universal (key in 12, 13, 50, 51 pins). A 32-bit slot has 62 contacts on each side, a 64-bit one - 94. This bus allows you to connect up to four devices simultaneously, that is, it can have up to four connectors. To use more connected devices, a special microcircuit is used - a bus bridge, to connect two buses.

PCI bus development

№	Year	Name
		PCI v.1.0
		PCI v.2.0 (PCI Plug & Play)
		PCI v.2.1 (PCI Power Manager)
		PCI v.2.2 (PCI Hot Plug)
		PCI-X v.1.0 (Mini PCI)
	2001-2002	PCI-X v.2.0 and PCI Express v.1.0 and PCI v.2.3
		PCI Express v.1.0a (PCI Express mini, PCI Bridge)
		PCI v.3.0, PCI Express x16 (Graphics)
		PCI Express v.1.1
		PCI Express v.2.0
		PCI Express v.3.0
	2013-2014	PCI Express v.4.0

PCI 2.2 - 64-bit bus width and / or 66 MHz clock frequency are allowed, i.e. peak throughput up to 533MB / sec

PCI-X - 64-bit PCI version 2.2 with increased frequency up to 133 MHz (peak bandwidth 1066MB / sec)

PCI-X 266 (PCI-X DDR), DDR version PCI-X (effective frequency 266 MHz, real frequency 133 MHz with transmission on both clock edges, peak bandwidth 2.1 GB / s

PCI-X 533 (PCI-X QDDDR) 6 QDR PCI-X version (533 MHz effective frequency, 4.3 GB / s peak bandwidth)

Mini PCI - PCI with SO-DIMM style slot, mainly used for miniature network, modem and other cards in laptops

Compact PCI - a standard for a form factor (modules are inserted from the end into a cabinet with a common bus at the rear) and a connector designed primarily for industrial computers and other critical applications

Accelerated Graphics Port (AGP) - high speed PCI version, optimized for graphics accelerators

Real frequency - the frequency at which data is transmitted (clock frequency).

Effective frequency - the frequency corresponding to the standard (real frequency multiplied by the number of bits transmitted per clock cycle). If two data bits are transmitted in one clock cycle, then the effective frequency will be twice the real one.

Local PCI bus for mobile

• PCI Express for mobile devices in the form of ExspressCard standard.
• Laptops and miniature desktops were the first to receive support for modules.

ExpressCard technology has replaced all outdated parallel buses, most of them use modern interfaces - PCI Express, USB 3.0

Local PCI bus

There are no more than 4 devices (slots) on one PCI bus.

PCI Bridge - (bus bridge) hardware means of connecting PCI to other buses.

• Host Bridge main bridge - for connecting PCI to the processor bus
• Peer to Peer Bridge peer-to-peer bridge - for connecting two PCI buses

PCI performance:

GT / s - giga-transfers / second (billion transfers per second). It is used as a numerical characteristic of the speed of working with the RAM of Intel processors.

The actual speed of the memory depends on the processor.

Conversion to Gbps for PCIe 3.0 (8x):

64GT / s * (128b / 130b) - 63.01Gbps

Local PCIe bus

PCI Express 2.0 has a signal transmission rate of 5 GT / s, which means the bandwidth is 500 MB / s for each lane.

PCI Express 2.0, which typically uses 16 lanes, offers bi-directional bandwidth up to 8 GB / s.

The PCI Experss 2.0 standard uses an 8b / 10b coding scheme, where 8 data bits are transmitted as 10-bit characters for error recovery. As a result, we get 20% redundancy, that is, a decrease in usable bandwidth.

PCI Express 3.0 uses a signaling rate of 8 GY / s, which translates into 1 GB / s bandwidth per lane (16 GB / s).

PCI Express 3.0 moves to a more efficient 1128b / 130b encoding scheme, eliminating 20% \u200b\u200bredundancy.

8 GT / s is the “theoretical” rate, and the actual rate is comparable in performance to the signal rate of 10 GT / s, if not for the 8b / 10b coding principle.

In 2011, PCI SIG announced the PCI Express (PCIe) 4.0 computer bus standard, which will deliver a record 16 gigatransfers per second per lane throughput, double the speed limit for PCIe 3.0.

16 GT / s corresponds to a speed of approximately 2 Gb / s per x1 lane.

1. USB bus. Development history, types, characteristics. Difference from IEEE 1394 FireWire

USB bus

Compaq, DEC, IBM, Intel, NEC and others (1993)

Requirements for the project:

• users should not set switches and jumpers
• users do not have to disassemble the system unit
• there must be a single connector for connecting devices
• i / O devices must be powered via cable
• the ability to connect up to 127 devices
• support for real-time devices
• the ability to install equipment without rebooting and shutting down the PC
• low production costs

USB 1.0 bus

In 1996, USB 1.0 (Universal Serial Bus) is a universal serial bus.

Industry standard for expanding PC architecture, focused on integration with peripheral devices.

2 baud rate modes:

• Low Speed \u200b\u200b(1.5 Mbps) - keyboard, joystick, mouse
• Full Speed \u200b\u200b(12 bit / s) - modems, scanners, printers

1998 USB 1.1 - problem fixes

USB 2.0 bus

In 2000 USB 2.0

One more operating mode High Speed \u200b\u200b480 Mbps is added for high-speed devices (HDD, digital cameras, etc.).

USB 3.0 bus

In 2008 USB 3.0

USB 3.0 and USB 3.1 Gen1 throughput up to 5Gbps.

The new USB 3.0 interface is called SuperSpeed \u200b\u200bUSB (SuperSpeed \u200b\u200bor SuperSpeed \u200b\u200bUSB).

USB 3.0 retains full compatibility with existing USB 2.0 equipment.

The USB 3.0 interface uses 8/10 bit encoding to ensure reliable data transfer.

One byte (8 bits) is transmitted using 10-bit encoding, which improves transmission reliability at the expense of bandwidth.

Ø The standard effectively optimizes energy consumption

Ø USB 2.0 interface constantly polls the availability of devices, which consumes energy

Ø USB 3.0 interface has four connection states, (U0-U3).

1) Connection status U0 corresponds to active data transmission.

2) If the connection is idle, then in the U1 state, the reception and transmission of data will be disabled.

3) State U2 disables internal clock pulses.

4) The U3 state puts the device to sleep.

USB 3.0 is backward compatible with USB 2.0.

The USB 2.0 pins remain in the same place, but five new pins are now located deep in the connector.

USB 3.1 bus

In 2015 USB 3.1 b and the new USB Type C connector

USB 3.1 SuperSpeed \u200b\u200b+

Feature USB 3.1 Gen2 - theoretical bandwidth increased to 10 Gbps

New Thunderbolt Controllers Deliver 20 Gbps, Upcoming 40 Gbps

At CES 2015, USB-IF representatives assembled a stand with a pair of SSDs in a RAID 0 array connected via USB 3.1. Test utility CrystalDisk Benchmark showed a linear write speed of 817 MB / s.

USB Power Delivery 2.0 specifications provide for an increase in current carrying capacity from 900 mA for USB 3.0 ports to 5000 mA for USB 3.1

Guaranteed enough to power large external hard drives and other powerful consumers from a single port.

The USB Type-C port will eventually provide power to almost all devices up to a hundred watts.

A special feature of USB-C is the symmetrical design of the connector, which allows it to be connected to the port either side. In terms of dimensions, it is identical to MicroUSB (8.3 * 2.5 mm).

Eight USB 3.1 pins can be used simultaneously for both file transfer and monitor connection via DisplayPort.

The rest provide power and connection of devices with the old uSB 2.0 interface, such as keyboards and mice.

Difference from IEEE 1394 FireWire
Serial FireWire and USB are essentially different technologies in common. Both buses provide easy connection of a large number of controllers (127 for USB and 63 for FireWire), allowing switching and turning on / off devices while the system is running. The topology of both buses is close enough. USB hubs are part of the control center; their presence is invisible to the user. Both buses have power lines for the devices, but the power handling capability for FireWire is much higher. Both buses support PnP (auto-configuration on / off) and eliminate the problem of address shortages, DMA channels and interrupts. Bandwidth and bus control differ.

USB is focused on PUs connected to PC. Its isochronous transmissions only transmit digital audio signals. All transmissions are controlled centrally and the PC is the necessary control node at the root of the bus tree structure. The connection of several PCs with this bus is not provided.

FireWire is focused on intensive communication between any devices connected to it. Isochronous traffic allows live video transmission. The bus does not require centralized control by the PC. It is possible to use the bus to combine several PCs and PUs into a local network.

New digital video and audio devices have built-in 1394 adapters. Connecting traditional analog and digital devices (players, cameras, monitors) to the FireWire bus is possible through interface and signal adapters. Standard, homogeneous FireWire cables and connectors replace many of the heterogeneous connections between consumer electronics devices and PCs. Diverse digital signals are multiplexed onto one bus. Unlike Ethernet networks, high-speed real-time data streams over FireWire do not require additional protocols. In addition, there are arbitration facilities to guarantee access to the bus within a specified time. FireWire bridging allows you to isolate host group traffic from each other.

1. Logical disk surface structure

A logical disk or volume (volume or partition) is a part of the long-term memory of a computer, considered as a whole for ease of operation. The term "logical disk" is used as opposed to "physical disk", which refers to the memory of one particular disk medium.

Disks refer to machine storage media with direct access. Concept direct access means that the PC can "refer" to the track on which the section with the required information begins or where new information needs to be written, directly, wherever the read / write head of the drive is.

Disk drives more varied:

• floppy disk drives (floppy disks), otherwise, on floppy disks or on floppy disks;
• hard disk drives (HDD) of the "hard drive" type;
• removable hard disk drives using the Bernoulli effect;
• optical CD-ROM drives (Compact Disk ROM);
• optical drives such as CC WORM (Continuous Composite Write Once Read Many - one-time write - multiple reading);
• drives on magneto-optical disks (NMOD), etc.

Magnetic disks (MD) refers to magnetic machine storage media. As a storage medium, they use magnetic materials with special properties (with a rectangular hysteresis loop), which make it possible to record two magnetic states - two directions of magnetization. Each of these states is assigned binary digits: 0 and 1. MD drives (CDM) are the most common external storage devices in a PC. Disks are rigid and flexible, removable and built into a PC.

A device for reading and writing information on a magnetic disk is called disk drive .

All disks: both magnetic and optical, are characterized by their diameter or, otherwise, form factor. The most widely used drives are 3.5 "(89 mm) drives. 3.5" drives with smaller dimensions have more capacity, shorter access times and faster read speeds (transfer), higher reliability and durability.

Information on the MD (Fig. 4.) is written and read magnetic headsalong concentric circles - tracks (tracks). The number of tracks on the MD and their information capacity depend on the type of MD, the design of the drive on the MD, the quality of the magnetic heads and the magnetic coating.

Figure: 4. The logical structure of the magnetic disk surface

Each MD track is divided into sectors . Sector is the smallest addressable unit of data exchange between a disk device and RAM. In order for the controller to be able to find the desired sector on the disk, it is necessary to set all the components of the sector address to it: surface number, cylinder (track) number and sector number.

One sector of a track usually contains 512 bytes of data. Data exchange between LMD and OP is carried out sequentially with an integer number of sectors.

Cluster is the smallest unit of information on the disk, consisting of one or more adjacent sectors of a track.

When writing and reading information, the MD rotates around its axis, and the magnetic head control mechanism brings it to the track selected for writing or reading information.

Data on disks is stored in files, which are usually identified with a site (area, field) of memory on these storage media.

File is a named area of \u200b\u200bexternal memory allocated to store an array of data.

The memory field for the created file is allocated a multiple of a certain number of clusters. Clusters allocated to a single file can be located in any free disk space and are not necessarily contiguous. Files stored in clusters scattered across the disk are called fragmented.

For packages of magnetic disks (disks are mounted on one axis) and for double-sided disks, the concept of "cylinder" is introduced.

Cylinder is called a set of MD tracks located at the same distance from its center.

1. External PC devices. Classification and detailed description.

External devices

• External storage devices or external memory
• Information input devices
• Information output devices
• Multimedia tools

External memory refers to external PC devices and is used for long-term storage of any information.

Classification based on:

• By type of carrier
• By construction type
• By the principle of writing and reading information
• By access method, etc.

OVC classification

1) External

Tape

Bobbin

Cassette

3) Disk

Magnetic

Replaceable

· Non-replaceable

Optical

Mixed

Floppy disks

• 3.5 inch
• 1.44 MB
• 300 rpm

Causes damage:

• Deforming a floppy disk
• Opening the safety shutter
• Magnet impact

HDD - Hard Disk Drive (ZHMD) - hard magnetic disk

• Rotational speed: 7200 rpm, 10000 rpm
• Connection: IDE, SATA

1. Audio CD

Diameter 12cm

74-80 minutes of sound

1. CD-ROM, CD-R, CD-RW

650-700 MB

CD-ROM - Read Only

CD-R - write once

CD-RW - rewritable

1. mini CD (-R, RW)

Diameter 8cm

24 minutes of sound, 210 MB

Advantages:

• reliability, durability
• low cost

Disadvantages:

• Low read / write speed

DVD (Video Disk) laser with a shorter wavelength

1) Single layer

• Single-sided 4.7 GB
• Double-sided 9.4 GB

2) Double layer

• One-sided 8.5
• Double-sided 17.1

DVD-ROM - Read Only

DVD-R, DVD + R - write once

DVD-RW, DVD-RW - rewritable (1000 cycles)

HD DVD - high definition DVD (high definition)

Development: Toshiba with NEC and SANYO

Supported by: Microsoft, Intel

Blu-ray Disk

Blu-ray Disk (BD) is a high-density optical disc format for storing data or high-definition video, using discs of standard 12 and 8 cm diameter and a blue laser with a wavelength of 405 nm.

BD-RE (rewritable)

Based on memory chips (up to 1 TB) (laptops, netbooks, phones, tablets)

Advantages:

• Do not make noise
• High read / write speed
• Light weight

Disadvantages:

• Limited number of write cycles (100,000)
• High price

Streamer

A streamer is a device for backing up data from a hard drive to a magnetic tape.

Advantages:

• Capacities up to 4TB
• Cheap magnetic tape
• Reliability
• High speed (up to 160 Mb / s)

Disadvantages:

• Sequential access to data (rewind "to the desired location)
• Low search speed
• For data flow only, it is extremely difficult to work with individual files

Manufacturers: Sony, IBM, Hewlett Packard

External devices

1. Information input devices

· Keyboard - a device for manual input of numerical, textual and control information into a computer;

· Graphic tablets (digitizers) - for manual input of graphic information, images by moving a special pointer (pen) on the tablet; when you move the pen, the coordinates of its location are automatically read and these coordinates are entered into the computer;

· Scanners (reading machines) - for automatic reading from paper carriers and entering into a computer typewritten texts, graphs, drawings, drawings;

Pointing devices (graphic manipulators) - for entering graphic information on the monitor screen by controlling the movement of the cursor across the screen, followed by coding the coordinates of the cursor and entering them into the computer (joystick, mouse, trackball, light pen);

Touch screens - to enter individual image elements, programs or commands from the split-screen display into a computer).

· Digital photo / camcorders allow receiving video images and photographs directly in digital format.

1. Information output devices

· Plotters (plotters) - for displaying graphic information on paper;

· Printers - printing devices for outputting information on paper.

The main types of printers:

• dot matrix - the image is formed from dots, the printing of which is carried out by thin needles hitting the paper through the ink ribbon. Characters in a line are printed sequentially. The number of pins in the print head determines the print quality. Inexpensive vdrinters have 9 needles. More advanced dot matrix printers have 18 and 24 needles;
• inkjet - there are thin tubes in the print head - nozzles through which tiny droplets of ink are thrown onto the paper. The printhead array typically contains 12 to 64 nozzles. Currently, inkjet printers provide a resolution of up to 50 dots per millimeter and print speeds of up to 500 characters per second with excellent print quality approaching laser print quality. Inkjet printers also perform color printing, but the resolution is reduced by about half;
• laser - an electrographic method of image formation is used. The laser is used to create an ultra-thin light beam that traces the contours of an invisible dotted electronic image on the surface of a pre-charged photosensitive drum. After the development of the electronic Imagination with a powder of dye (toner) adhering to the discharged areas, printing is performed - the transfer of toner from the drum to the paper and the image is fixed on the paper by warming up the toner until it melts. Laser printers provide the highest quality printing at high speed. Color laser printers are widely used.

User Dialogue Tools

• video terminals (monitors) are devices for displaying input and output information. The video terminal consists of a video monitor (display) and a video controller (video adapter). Video controllers are part of the computer system unit (located on the video card installed in the motherboard connector). Video monitors are external devices on your computer. The main characteristic of the monitor is its resolution, which is determined by the maximum number of dots located horizontally and vertically on the monitor screen. Modern monitors have standard resolutions ranging from 640 X 480 to 1600 x 1200, but there may be other values \u200b\u200bin reality. Both color and monochrome monitors can be used;

The main characteristic of the monitor is the maximum number of dots located horizontally and vertically on the screen.

The screen size is set by the size of its diagonal in inches

For example: 17 "", 42 "", 48 ""

Screen resolution from 640 * 480px, 5120 * 2880px

• devices for speech input-output of information. These include various microphone acoustic systems, as well as various sound synthesizers that convert digital codes into letters and words, played through speakers or sound speakers connected to a computer.

Communications and telecommunications

· Network adapters (modem - modulator-demodulator) are used to connect a computer to communication channels, other computers and computer networks.

· Faxes - These are devices for facsimile transmission (exact reproduction of a graphic original (signature, document, etc.) by means of printing) of an image over the telephone network.

· Fax modems - modems that can send and receive data like a fax.

1. External PC devices (types of I / O ports, classification). Multimedia concept.

VESA (Video Electronics Standards Association) has published the DisplayPort 1.3 standard.

Throughput up to 32.4 Gb / s (8.1 Gb / s on each of the four lines). Taking into account the overhead of transmission, the uncompressed video stream speed can reach 25.92 Gbps.

Convert video to vga, dvi, hdvi

HDCP 2.2 and hdmi 2.0 support with cec (TV application, copy protection)

Support for 4: 2: 0 aspect ratio, used in consumer television interfaces

Improved capabilities to transfer Display Port simultaneously with video of other data, such as USB 3.0

List of I / O ports commonly used in a personal computer:

1. Parallel (LPT)
2. Serial (COM)
3. Game
4. Ethernet connector
5. PS / 2 connector (mouse)
6. PS / 2 connector (keyboard)
7. VGA connector and other video outputs
8. Audio jacks for connecting speakers, microphone, etc.

I / O ports on an ATX motherboard:

1 - PS / 2 connector (mouse); 2 - PS / 2 connector (keyboard); 3 - Ethernet output; 4 - Two USB connectors; 5 - Serial port connector; 6 - Parallel port connector; 7 - VGA connector; 8 - Game port; 9 - Audio ports (from left to right: line-out, input, microphone).

Parallel port (LPT)

The main feature of a parallel port is the simultaneous transmission of data over several lines. This feature brings LPT closer to the internal buses of a computer. The main purpose of a parallel port is to connect external devices, and in most cases such a device is a printer.

The first versions of the parallel port had one-way directionality, that is, data could be transmitted over the cable only in one direction - to the peripheral device. Later, improved LPT interface standards were introduced, in which data could be transferred in both directions.

Serial port (COM)

This port is distinguished by serial data transmission over one line. Serial transmission means that bits of information are transmitted over the line one after the other. In addition, serial port communication is bidirectional. Typically, COM is for connecting peripheral devices such as a mouse or modem. The port connector on the computer motherboard uses a 9-pin DE-9 male connector.

Game port

This port is not very common on motherboards these days. In addition, it is not supported by modern operating systems such as Windows 7. However, it can still be seen on sound cards. The port connector is a 15-pin connector.

As you might guess from the name of the port, it is intended primarily for connecting joysticks. A feature of the port is the ability to connect two devices to it at once. In addition, in sound cards, the game port is often used to connect MIDI devices such as synthesizers. Since it is capable of working with analog and analog-to-digital devices, an analog-to-digital converter is built into the microcircuit serving it.

The PS / 2 connector is used on a computer to connect a mouse and / or keyboard. Despite the fact that it was developed a long time ago, back in the mid-1980s, nevertheless, it is still actively used in computers. Some motherboards have two universal connectors to which you can connect both a mouse and a keyboard, while others have two separate connectors for a mouse and keyboard. In this case, the green connector is intended for connecting a mouse, blue - for the keyboard. Both connectors are 9-pin mini-DIN.

The USB port, which will be described in detail in a separate article, is the fastest, most versatile and productive I / O port in modern computers. It is for this reason that USB has practically supplanted many other ports. Typically, a computer has multiple connectors for connecting USB devices.

Multimedia - an interactive system that provides the simultaneous presentation of various media - sound, animated computer graphics, video. For example, in one container object ( container) may contain textual, audio, graphic and video information, as well as, possibly, a way of interacting with it.

Multimedia tools is a set of hardware and software tools that allow a person to communicate with a computer using a variety of natural environments: sound, video, graphics, texts, animation, etc. Multimedia means include:

• devices for speech input and output of information;
• microphones and video cameras, acoustic and video reproducing systems with amplifiers, speakers, large video screens;
• sound and video cards, video capture cards that capture images from a VCR or camcorder and enter it into a computer;
• scanners;
• external mass storage devices on optical discs, often used for recording audio and video information
• video editors;
• professional graphic editors;
• means for recording, creating and editing audio information, allowing you to prepare sound files for inclusion in programs, change the amplitude of the signal, superimpose or remove the background, cut or paste data blocks at a certain time interval;
• programs for manipulating image segments, changing colors, palettes;
• programs for the implementation of hypertext, etc.

Readers of the site will probably remember our similar project, which we already carried out about two and a half years ago. we analyzed PCI Express bandwidth in November 2004, when the PCI Express (PCIe) interface was still new and did not offer a significant advantage over AGP graphics cards. Today, almost every new computer has a PCI Express interface; it is also used to connect a video card, both built-in and external. Over the past time, video cards have made significant progress, so it seemed to us that the time has come for a new analysis, which would answer the question: what bus bandwidth does a video card really need?

PCI Express quickly brought the graphics industry to growth as it allowed nVidia and ATi / AMD to put two or even four video cards in a computer. In addition, PCI Express is required for expansion cards with high bandwidth requirements such as RAID controllers, Gigabit NICs, or physical accelerators for 3D applications and games. The processing power of additional graphics cards can be used to increase performance at high resolutions, add visual features, or to increase speed at standard resolutions and quality settings. However, the latter option is not always interesting, since many modern video cards are powerful enough for standard resolutions of 1024x768 and 1280x1024. The upside potential with ATi CrossFire and nVidia SLI is impressive, but both require the right platform. But a wagon, that is, a motherboard that would support CrossFire and SLI at the same time, does not exist. At least for now.

However, configurations on two and four video cards are only part of the graphics market. Most computers and upgrade scenarios are still based on a single graphics card, which is why we decided not to expand our PCI Express scaling tests to two graphics cards. We took regular high-end ATi and nVidia video cards and ran them through a series of tests in different PCI Express modes.

The most common PCI Express slots: the large one supports 16 lines, and the small one - one line for the simplest expansion cards.

Unlike PCI and PCI-X buses, PCI Express is based on a point-to-point serial protocol. That is, the PCI Express interface requires a relatively small number of wires. On the other hand, the interface uses much higher clock rates compared to parallel buses, which gives high bandwidth. Additionally, bandwidth can be easily increased by linking multiple PCI Express lanes together. The most commonly used slot types are x16, x8, x4, x2, and x1, where the numbers indicate the number of PCI Express lanes.

PCI Express is a bi-directional point-to-point interface that provides the same bandwidth in both directions, and does not need to share bandwidth with other devices, as was the case with PCI. Thanks to the modular architecture, motherboard manufacturers can map the available PCI Express lanes to the slots they require. Let's say 20 available PCI Express lanes can be routed to one x16 PCIe slot and four x1 PCIe slots. This is what happens with many chipsets. And for server systems, for example, you can install five x4 PCIe ports. In general, any mathematical configuration can be created with PCI Express. Finally, PCI Express allows mixing chipset bridges from different manufacturers.

However, PCI Express has one drawback: the more PCIe lanes, the higher the chipset's power consumption. It is for this reason that chipsets with 40 or more PCI Express lanes require more power. Typically, 16 additional PCI Express lanes increase power consumption of modern chipsets by 10W.

PCI Express Lines	Throughput in one direction	Total throughput
1	256 MB / s	512 MB / s
2	512 MB / s	1 GB / s
4	1 GB / s	2 GB / s
8	2 GB / s	4 GB / s
16	4 GB / s	8 GB / s

Most motherboards use 16 PCI Express lanes to connect to a video card.

On many dual-graphics systems, the two physical x16 PCI Express slots operate at x8 lanes each.

To make the video card work in x8 PCI Express mode, we sealed some of the contacts with tape.

For the video card to work in x4 PCI Express mode, we had to tape even more contacts with tape.

The same video card, but more contacts are glued. It operates in x4 PCI Express mode.

The same can be said about x1 PCI Express. We sealed all contacts that were not required in x1 mode.

If you glue the extra contacts, then the PCI Express video card will work in only x1 PCI Express mode. The throughput is 256 MB / s in both directions.

Please note that not every motherboard can work with video cards with a low number of PCI Express lanes. In our first article , we had to change the BIOS of the DFI LANParty 925X-T2 motherboard to support "low" modes. As for the new motherboards, we also had to check several models before we found the right one. Ultimately we settled on the MSI 975X Platinum PowerUp Edition. The Gigabyte 965P-DQ6 did not work right from the start, and Asus Commando refused to work in "low" modes after updating the BIOS.

X16 PCI Express slot diagram. From it you can determine which contacts needed to be sealed with tape. Click on the picture to enlarge.

Competitors: ATi Radeon X1900 XTX and nVidia GeForce 8800 GTS

We took two high-end video cards from two competitors: AMD / ATi and nVidia, namely the Radeon X1900 XTX and GeForce 8800 GTS. The models, of course, are not the top-end ones, but definitely high-end ones.

The ATi Radeon X1900 XTX consists of 384 million transistors and offers 48 pixel shader units. They are organized in four blocks in the so-called "quads". The GPU runs at 675 MHz and has 512 MB of GDDR3 memory clocked at 775 MHz (1.55 GHz DDR). Please note that ATi X1xxx graphics cards are not DirectX 10.

We took the HIS X1900 XTX IceQ3 model, which uses an improved cooling system. Since the design is reference, the card fan is still radial, but there is a heat pipe system and a massive heatsink. In our experience, the HIS graphics card is quieter than the ATi reference models.

Nvidia's GeForce 8 line is the company's leading edge. Although we have the first consumer-grade DirectX 10 graphics cards, nVidia didn't get off to a great start on Windows Vista due to driver issues. The chip is clocked at 500 MHz, while the pixel processors are clocked at 1.2 GHz. There are cards on sale with 320 and 640 MB of RAM, all of which use 800 MHz memory (1.6 GHz DDR).

We took a GeForce 8800 GTS with 320 MB of GDDR3 memory from Zotec. The card is built according to the nVidia reference design.

Test configuration

System hardware
Socket 775	Intel Core 2 Extreme X6800 (Conroe 65nm, 2.93GHz, 4MB L2 cache)
Motherboard	MSI 975X Platinum PowerUp Edition, Chipset: Intel 975X, BIOS: 2007-01-24
General hardware
Memory	2x 1024 MB DDR2-8000 (CL 4,0-4-4-12), Corsair CM2X1024-6400C3 XMS6403v1.1
Graphics card I	HIS X1900 XTX IceQ3, GPU: ATi Radeon X1900 XTX (650 MHz), memory: 512 MB GDDR3 (1,550 MHz)
Graphics card II	Zotec GeForce 8800 GTS, GPU: GeForce 8800 GTS (500 MHz), memory: 320 MB GDDR3 (1200 MHz)
HDD	400 GB, 7,200 rpm, 16 MB cache, SATA / 300, Western Digital WD4000KD
DVD-ROM	Gigabyte GO-D1600C (16x)
Software
Graphics driver I	ATi Catalyst Suite 7.2
Graphics Driver II	nVidia ForceWare 97.92
Intel Platform Drivers	Chipset Installation Utility 8.1.1.1010
DirectX	Version: 9.0c (4.09.0000.0904)
OS	Windows XP Professional, Build 2600 SP2

Tests and settings

Tests and settings
3D games
	Version: 1.3 Retail Video Mode: 1600x1200 Anti Aliasing: 4x Texture Filter: Anisotropic Timedemo demo2
	Version: 1.2 (Dual-Core Patch) Video Mode: 1600x1200 Video Quality: Ultra (ATI) / High (Nvidia) Anti Aliasing: 4x Multi CPU: Yes THG Timedemo waste.map timedemo demo8.demo 1 (1 \u003d load textures)
Applications
SPECviewperf 9	Version: 9.03 All Tests
3D Mark06	Version: 1.1 Video Mode: 1600x1200 Anti Aliasing: 4x Anisotropic Filter: 8x

Test results

As you can see, the nVidia GeForce 8800 GTS works at x1 and x4 speeds just awful, noticeably lower than the maximum performance level that can be achieved only at x16 speeds. The ATi Radeon X1900 XTX, on the other hand, requires no more than x4 PCI Express bandwidth to run properly in Call of Duty 2.

The situation in Quake 4 is completely different. Here ATi Radeon X1900 XTX and nVidia GeForce 8800 GTS start to work quite normally at x4 PCI Express speeds, and they win insignificantly when moving to x8 or x16.

Futuremark's 3D graphics benchmark, 3DMark06, puts a heavy load on the GPU as it has been designed for a similar purpose from the very beginning. Therefore, the requirements for the interface are low. The nVidia GeForce 8800 GTS is more responsive to PCI Express bandwidth drops compared to the ATi Radeon X1900 XTX, which runs close to maximum already at x4 PCI Express speeds.

Professional graphics OpenGL-test SPECviewperf 9.03 is very heavy load of the central processor and graphics subsystem. As you can see, the results significantly depend on the interface speed. It was curious to note how performance scales from x1 to x4 to x8 PCI Express. The transition to x16 PCI Express gives a performance increase, but not so significant. In any case, it's pretty clear that professional graphics applications require a high bandwidth interface. Therefore, if you want to work with 3DSMax, Catia, Ensight, Lightscape, Maya, Pro Engineer or SolidWorks, then you cannot do without x16 PCI Express.

Conclusion

Conclusion of our pCI Express scaling analysis in 2004 was simple: the x4 PCIe bandwidth is sufficient for single video cards, without creating a "bottleneck". At that time, the bandwidth of x8 or x16 PCIe interfaces did not give any gain, and the AGP interface, in principle, was also enough.

But in our time the situation has changed. As you can see, four PCI Express lanes are no longer enough to get maximum performance. While we see differences between ATi / AMD and nVidia and between games and professional applications, in most cases, maximum performance is only achieved with the x16 PCI Express interface. We tested two 3D games, Quake 4 and Call of Duty 2, which aren't the most demanding games today, but they definitely benefit from a faster interface. But the most interesting results we got in the SPECviewperf 9.03 test, as it showed a significant performance drop when the PCI Express interface speed drops below x16.

The performance results clearly show that motherboards and chipsets today must support all graphics cards at full x16 PCI Express speed. If you install high-performance graphics cards on a "weak" interface such as PCI Express x8, then you will have to sacrifice performance.

In the spring of 1991, Intel completed the development of the first prototype PCI bus. The engineers were tasked with developing an inexpensive and productive solution that would allow the 486, Pentium and Pentium Pro processors to be realized. In addition, it was necessary to take into account the mistakes made by VESA when designing the VLB bus (the electrical load did not allow connecting more than 3 expansion cards), and also to implement automatic device configuration.

In 1992, the first version of the PCI bus appears, Intel announces that the bus standard will be open, and creates the PCI Special Interest Group. Thanks to this, any interested developer can create devices for the PCI bus without the need to purchase a license. The first version of the bus had a clock frequency of 33 MHz, could be 32- or 64-bit, and the devices could work with signals of 5 V or 3.3 V. Theoretically, the bus bandwidth was 133 MB / s, but in reality the bandwidth was about 80 MB / s.

Main characteristics:

• bus frequency - 33.33 or 66.66 MHz, synchronous transmission;
• bus width - 32 or 64 bits, the bus is multiplexed (address and data are transmitted over the same lines);
• peak throughput for the 32-bit version, operating at 33.33 MHz - 133 MB / s;
• memory address space - 32 bits (4 bytes);
• address space of input-output ports - 32 bits (4 bytes);
• configuration address space (for one function) - 256 bytes;
• voltage - 3.3 or 5 V.

Photo of connectors:

MiniPCI - 124 pin
MiniPCI Express MiniSata / mSATA - 52 pin
Apple MBA SSD, 2012
Apple SSD, 2012
Apple PCIe SSD
MXM, Graphics Card, 230/232 pin
MXM2 NGIFF 75 pins KEY A PCIe x2 KEY B PCIe x4 Sata SMBus
MXM3, Graphics Card, 314 pin
PCI 5V
PCI Universal
PCI-X 5v
AGP Universal
AGP 3.3 v
AGP 3.3 v + ADS Power
PCIe x1
PCIe x16
Custom PCIe
ISA 8bit
ISA 16bit
eISA
VESA
NuBus
PDS
PDS
Apple II / GS Expasion slot
PC / XT / AT expasion bus 8 bit
ISA (industry standard architecture) - 16 bit
eISA
MBA - Micro Bus architecture 16 bit
MBA - Micro Bus architecture with 16 bit video
MBA - Micro Bus architecture 32 bit
MBA - Micro Bus architecture with 32 bit video
ISA 16 + VLB (VESA)
Processor Direct Slot PDS
601 Processor Direct Slot PDS
LC Processor Direct Slot PERCH
NuBus
PCI (Peripheral Computer Interconnect) - 5v
PCI 3.3v
CNR (Communications / network Riser)
AMR (Audio / Modem Riser)
ACR (Advanced communication Riser)
PCI-X (PCI Peripheral) 3.3v
PCI-X 5v
PCI 5v + RAID option - ARO
AGP 3.3v
AGP 1.5v
AGP Universal
AGP Pro 1.5v
AGP Pro 1.5v + ADC power
PCIe (peripheral component interconnect express) x1
PCIe x4
PCIe x8
PCIe x16

PCI 2.0

The first version of the basic standard, which became widespread, used both cards and slots with a signal voltage of only 5 volts. Peak throughput - 133 MB / s.

PCI 2.1 - 3.0

They differed from version 2.0 by the possibility of simultaneous operation of several bus masters (English bus-master, the so-called competitive mode), as well as the appearance of universal expansion cards capable of operating both in slots using a voltage of 5 volts and in slots using 3 , 3 volts (with a frequency of 33 and 66 MHz, respectively). The peak bandwidth for 33 MHz is 133 MB / s, and for 66 MHz it is 266 MB / s.

• Version 2.1 - work with 3.3 volt cards and the presence of the corresponding power lines were optional.
• Version 2.2 - expansion cards made in accordance with these standards have a universal power connector key and are able to work in many later varieties of PCI bus slots, as well as, in some cases, in version 2.1 slots.
• Version 2.3 is incompatible with PCI cards rated for 5 volts, despite the continued use of 32-bit slots with a 5-volt key. Expansion cards have a universal connector, but are not able to work in 5-volt slots of earlier versions (up to 2.1 inclusive).
• Version 3.0 - Completes the transition to 3.3 volt PCI cards, 5 volt PCI cards are no longer supported.

PCI 64

An extension to the basic PCI standard introduced in version 2.1 that doubles the number of data lines, and therefore the bandwidth. The PCI 64 slot is an extended version of the regular PCI slot. Formally, the compatibility of 32-bit cards with 64-bit slots (subject to the presence of a common supported signal voltage) is complete, and the compatibility of a 64-bit card with 32-bit slots is limited (in any case, performance will be lost). Works at a clock frequency of 33 MHz. Peak throughput is 266 MB / s.

• Version 1 - Uses a 64-bit PCI slot and 5 volts.
• Version 2 - Uses a 64-bit PCI slot and 3.3 volts.

PCI 66

PCI 66 is a 66 MHz development of PCI 64; uses 3.3 volts in the slot; the cards have a universal or 3.3V form factor. Peak throughput is 533 MB / s.

PCI 64/66

The combination of PCI 64 and PCI 66 allows up to four times the data transfer rate over the base PCI standard; Uses 64-bit 3.3-volt slots only compatible with universal and 3.3-volt 32-bit expansion cards. PCI64 / 66 cards have either universal (but limited compatibility with 32-bit slots) or 3.3V form factor (the latter option is fundamentally incompatible with 32-bit 33MHz slots of popular standards). Peak throughput - 533 MB / s.

PCI-X

PCI-X 1.0 - expansion of the PCI64 bus with the addition of two new operating frequencies, 100 and 133 MHz, as well as a mechanism for separate transactions to improve performance when multiple devices work simultaneously. Generally backward compatible with all 3.3V and general purpose PCI cards. PCI-X cards usually run in 64-bit 3.3V format and have limited backward compatibility with PCI64 / 66 slots, and some PCI-X cards are in a universal format and are able to work (although this has almost no practical value) in the usual PCI 2.2 / 2.3. In difficult cases, in order to be completely sure that the combination of the motherboard and the expansion card is working, you need to look at the compatibility lists of the manufacturers of both devices.

PCI-X 2.0

PCI-X 2.0 - further expands the capabilities of PCI-X 1.0; added frequencies 266 and 533 MHz, as well as - data transmission parity error correction (ECC). Allows splitting into 4 independent 16-bit buses, which is used exclusively in embedded and industrial systems; the signal voltage has been reduced to 1.5 V, but the connectors are backward compatible with all cards using a signal voltage of 3.3 V. Currently, for the non-professional segment of the market for high-performance computers (powerful workstations and entry-level servers), in which it is used PCI-X bus, very few motherboards with bus support are produced. An example of a motherboard for such a segment is the ASUS P5K WS. In the professional segment, it is used in RAID controllers, in SSD drives for PCI-E.

Mini PCI

Form factor PCI 2.2, designed for use primarily in laptops.

PCI Express

PCI Express or PCIe or PCI-E (also known as 3GIO for 3rd Generation I / O; not to be confused with PCI-X and PXI) - computer bus (although it is not a bus at the physical level, being a point-to-point connection) using program model PCI bus and high-performance physical protocol based on serial data transmission... The development of the PCI Express standard was started by Intel after the abandonment of the InfiniBand bus. Officially, the first basic PCI Express specification appeared in July 2002. PCI Express is being developed by the PCI Special Interest Group.

Unlike the PCI standard, which used a common bus for data transfer with several devices connected in parallel, PCI Express, in general, is a packet network with star topology... PCI Express devices communicate with each other through a switch environment, with each device directly connected through a point-to-point connection to the switch. In addition, the PCI Express bus supports:

• hot swap of cards;
• guaranteed bandwidth (QoS);
• energy management;
• control of the integrity of the transmitted data.

The PCI Express bus is intended to be used only as a local bus. Since the PCI Express software model is largely inherited from PCI, existing systems and controllers can be modified to use the PCI Express bus by replacing only the physical layer, without modifying the software. The high peak performance of the PCI Express bus makes it possible to use it instead of AGP buses and especially PCI and PCI-X buses. De facto PCI Express has replaced these buses in personal computers.

• MiniCard (Mini PCIe) is a replacement for the Mini PCI form factor. The following buses are brought out to the Mini Card slot: x1 PCIe, 2.0 and SMBus.
  • M.2 is the second version of Mini PCIe, up to x4 PCIe and SATA.
• ExpressCard is similar to the PCMCIA form factor. The ExpressCard slot has x1 PCIe and USB 2.0 buses, ExpressCards support hot plugging.
• AdvancedTCA, MicroTCA - form factor for modular telecommunications equipment.
  
• The Mobile PCI Express Module (MXM) is an industrial form factor designed for notebooks by NVIDIA. It is used to connect graphics accelerators.
• PCI Express cable specifications make it possible to increase the length of one connection to tens of meters, which makes it possible to create a computer with peripheral devices located at a considerable distance.
  
• StackPC is a specification for building stackable computer systems. This specification describes the expansion connectors StackPC, FPE and their mutual arrangement.

Despite the fact that the standard allows x32 lines per port, such solutions are physically rather cumbersome and not available.

Year release	Version PCI Express	Coding	Speed transmission	Throughput on x lines
				× 1	× 2	× 4	× 8	× 16
2002	1.0	8b / 10b	2.5 GT / s	2	4	8	16	32
2007	2.0	8b / 10b	5 GT / s	4	8	16	32	64
2010	3.0	128b / 130b	8 GT / s	~7,877	~15,754	~31,508	~63,015	~126,031
2017	4.0	128b / 130b	16 GT / s	~15,754	~31,508	~63,015	~126,031	~252,062
2019	5.0	128b / 130b	32 GT / s	~32	~64	~128	~256	~512

PCI Express 2.0

The PCI-SIG released the PCI Express 2.0 specification on January 15, 2007. The main innovations in PCI Express 2.0:

• Increased bandwidth: 500 MB / s single line bandwidth, or 5 GT / s ( Gigatransactions / s).
• Improvements have been made to the transfer protocol between devices and the programming model.
• Dynamic speed control (to control the speed of communication).
• Bandwidth alert (to notify the software about changes in bus speed and width).
• Access Control Services - Optional point-to-point transaction management capabilities.
• Execution timeout control.
• Function level reset - an optional mechanism for resetting functions (PCI functions) inside a device (PCI device).
• Override the power limit (to override the slot power limit when connecting devices that consume more power).

PCI Express 2.0 is fully compatible with PCI Express 1.1 (old ones will work in motherboards with new connectors, but only at 2.5 GT / s, since older chipsets cannot support double data transfer rate; new video adapters will work without problems in old PCI Express 1.x slots).

PCI Express 2.1

In terms of physical characteristics (speed, connector) it corresponds to 2.0, in the software part, functions have been added that are fully planned to be introduced in version 3.0. Since most motherboards are sold with version 2.0, the presence of only a video card with 2.1 does not allow using the 2.1 mode.

PCI Express 3.0

PCI Express 3.0 specifications were approved in November 2010. The interface has a baud rate of 8 GT / s ( Gigatransactions / s). But, despite this, its real bandwidth was still doubled compared to the PCI Express 2.0 standard. This was achieved thanks to the more aggressive 128b / 130b encoding scheme, where 128 bits of data sent over the bus are encoded with 130 bits. At the same time, full compatibility with previous PCI Express versions has been preserved. PCI Express 1.x and 2.x cards will work in slot 3.0, and conversely, a PCI Express 3.0 card will work in 1.x and 2.x slots.

PCI Express 4.0

The PCI Special Interest Group (PCI SIG) said that PCI Express 4.0 could be standardized before the end of 2016, but by mid-2016, with a number of chips in preparation for production, the media reported that standardization was expected in early 2017. It is expected to be will have a bandwidth of 16 GT / s, that is, it will be twice as fast as PCIe 3.0.

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The operating modes of the PCI and ISA system buses are very important. Setting incorrect values \u200b\u200bcan lead to unstable operation of expansion cards and conflicts between them. Option Location - Item CHIPSET FEATURES SETUP Advanced(AWARD BIOS 6.0), Advanced Chipset Features

PCI 2.1 Support- PCI bus specification 2.1 support. For all modern computers, this mode must be enabled. (Enabled) ... An exception is possible only if your computer has outdated PCI expansion cards that do not support this specification. But then some PCI cards will refuse to work.

CPU to PCI Write Buffer- use of the buffer when transferring data from the processor to the PCI bus. Inclusion (Enabled)this mode has a positive effect on the computer's performance.

PCI Pipeline (PCI Pipelining) - inclusion (Enabled)this option combines the accumulation of data from the processor to the PCI bus with their pipelining, which naturally improves performance.

PCI Dynamic Bursting- enable batch mode of data transfer via PCI bus. To improve performance, this option must be enabled (Enabled).

PCI Master About WS Write- disabling the delay when exchanging between master devices on the PCI bus and RAM. When turned on (Enabled)this mode increases the overall performance of the computer, but in case of unstable operation of expansion cards, this option will have to be disabled (Disabled).

Delayed Transaction (PCI Delay Transaction) - enabling this parameter allows you to simultaneously access both slow ISA cards and fast PCI cards, which significantly increases overall performance. Disabling this option makes it impossible to access devices using the PCI bus during access to cards connected to the ISA bus. Naturally, when using ISA cards in your computer, this parameter must be enabled. (Enabled).

Peer Concurrency- allows parallel operation of several devices connected to the PCI bus. Naturally, to ensure maximum performance, the parameter must be enabled (Enabled) ... But not all expansion cards - especially older ones - support this feature. If after enabling this option you encounter unstable computer operation, specify the value Disabled.

Passive Release- allows parallel operation of PCI and ISA buses. Inclusion (Enabled)this option has a positive effect on the computer's performance.

PCI Latency Timer- the maximum number of PCI bus cycles during which a device connected to this bus can keep the bus busy if another device also needs access to the bus. A bus hold for 32 clock cycles is usually allowed. Increase this value if you see error messages for individual expansion cards or experience erratic performance.

16 Bit I / O RecoveryTime - indicates the delay in clock cycles after the issuance of a read or write request and the operation itself for 16-bit expansion cards connected to the ISA bus. For starters, you can try to set a minimum delay of 1 clock. If errors occur when working with such devices, increase the delay (maximum 4 clock cycles). If no sixteen-bit expansion cards are connected to the ISA bus at all, you can specify the value NA .

AGP bus and video cards

Option Location - Menu Items BIOS FEATURES SETUP, CHIPSET FEATURES SETUP and INTEGRATED PERIPHERALS (AWARD BIOS 4.51PG and AMIBIOS 1.24), Advanced(AWARD BIOS 6.0), Advanced Chipset Features and Integrated peripherals(AWARD BIOS 6.0PG and AMIBIOS 1.45).

AGP Aperture Size (Graphics Aperture Size, Graphics Windows Size) - the maximum size of RAM that can be used to store textures of a video card with an AGP interface. Generally, 64 MB is optimal.

AGP-2X (4X, 8X) Mode (AGP 4X Supported, AGP 8X Supported) - support for AGP2x (4X, 8X) mode. This parameter should be set only if your video card connected to the AGP bus is capable of working in these modes without any problems. For all modern video cards, support must be enabled (Enabled).

AGP Mode (AGP Capability) - allows you to specify the used AGP mode. All modern video cards must have 8X support enabled.

AGP Master1 WS Write- adding one clock cycle when writing data via the AGP bus. As a rule, this is not necessary and it is better to disable this option. (Disabled) , and only if the video card became unstable after that, artifacts appeared, especially in games, turn on (Enabled)additional waiting tact.

AGP Fast Write- actually the same as option AGP Master1 WS Write.When turned on (Enabled)this option, data is written without delay, when turned off (Disabled)one measure of waiting is added.

AGP Master1 WS Read- adding one clock cycle when reading data via the AGP bus. The recommendations are the same.

AGP to DRAM Prefetch- enable the prefetch mode when the next data is read automatically. Using (Enabled)this option improves performance.

PCI / VGA Palette Snoop- allows you to synchronize the colors of the video card and the image captured using the video input-output card (video editing card). If the colors are displayed incorrectly when capturing video, enable the option (Enabled).

Assign IRQ For VGA- enabling this option instructs to reserve an interrupt for the video card. Although most modern video cards do not feel the need for a separate interrupt, from a compatibility and stability point of view, this option is still better to enable (Enabled) ... And only in case of a lack of free interrupts (with a large number of expansion cards), you can try to refuse redundancy (Disabled).