PCI-E x16 slot: features and reviews. PCI-E x16 graphics card

Almost all modern motherboards are currently equipped with an expansion slot PCI-E x16. This is not surprising: it is installed discrete graphics accelerator, without which the creation of a productive personal computer is impossible. It is about his prehistory of appearance, technical specifications and possible modes of operation that will be discussed later.

The history of the expansion slot appearance

In the early 2000s, with the expansion slot AGP, which at that time was used to install discrete graphics cards, there was a situation where the maximum level of performance is reached and its capabilities are no longer enough. As a result, a consortium was created PCI-SIG, which began to develop the software and hardware components of the future slot for installing graphics accelerators. The fruit of his work and became in 2002 the first specification PCI Express 16x 1.0.

Some companies to develop compatibility of the two existing discrete graphics adapter ports at the time were developing special devices that allowed installing outdated graphics solutions in a new expansion slot. In the language of professionals, this development had its name - the PCI-E x16 / AGP adapter. Its main purpose is to minimize the cost of upgrading the PC by using the components from the previous configuration of the system unit. But this practice was not widely spread because the entry-level video cards on the new interface had a cost almost equal to the price of the adapter.

Simultaneously, simpler modifications of this expansion slot were also created for external controllers, which replaced the usual PCI ports at the time. Despite the external similarity, these devices differed significantly. If AGP and PCI could boast of parallel transmission of information, then PCI Express was a consistent interface. Its higher performance was provided by the significantly increased data transfer rate in duplex mode (information in this case could be transmitted in two directions at once).

Transmission speed and encryption method

In the designation of the PCI-E x16 interface The figure indicates the number of bands involved for data transmission. In this case, there are 16. Each of them, in turn, consists of 2 pairs of wires for transferring information. As noted, higher speed is ensured by the fact that these pairs operate in duplex mode. That is, the transfer of information can go in two directions at once.

To protect against possible losses or distortion of transmitted data, a special information protection system, called 8V / 10V, is used in this interface. This designation is deciphered as follows: for correct and correct transmission of 8 data bits, it is necessary to supplement them with 2 service bits to perform validation. In this case, the system has to transfer 20 percent of the service information, which for the user of the computer does not carry a payload. But this is a fee for reliable and stable operation of the graphic subsystem of a personal computer, and without this, certainly not to do.

PCI-E Versions

The PCI-E x16 connector is externally the same on all motherboards. Only here the speed of information transfer in each case can significantly differ. As a result, the speed of the device is also different. A modification of this graphical interface is:

• 1st modification of PCI-Express x16 v. 1.0 had a theoretical throughput of 8 Gb / s.
• 2nd generation PCI-Express x16 v. 2.0 already boasted twice the bandwidth - 16 GB / s.
• A similar trend has been maintained for the third version of this interface. In this case, this indicator was set at 64 Gb / s.

Visually distinguish by the location of contacts these slots are impossible. At the same time they are compatible with each other. For example, if you install a graphics adapter in the 3.0 slot, which corresponds at the physical level to specifications 2.0, then the entire graphics processing system will automatically switch to the slowest mode (that is, 2.0) and will continue to function with a bandwidth of 64 GB /from.

The first generation of PCI Express

As it was mentioned earlier, for the first time PCI Express was introduced in 2002. Its output marked the emergence of personal computers with several graphics adapters, which also boasted even with one installed accelerator increased speed. AGP 8X standard allowed to get throughput 2.1 Gb / s, and the first revision of PCI Express - 8 Gb / s.

Of course, talking about an eightfold increase is not necessary. 20 percent of the increase was used to transfer the service information, which allowed finding errors.

The second modification of PCI-E

In place of the first generation of this graphical interface in 2007 came PCI-E 2. 0 x16. Video cards of the 2nd generation, as noted earlier, were physically and programmatically compatible with the first modification of this interface. Only in this case the speed of the graphics system to the level of the version of PCI Express 1.0 16x was significantly reduced.

Theoretically, the limit of information transmission in this case was 16 Gb / s. But 20 percent of the increase was spent on official information. As a result, in the first case, the actual transmission was equal to: 8 Gb / s - (8 Gb / s x 20%: 100%) = 6.4 Gb / s. And for the second version of the graphic interface, this value was already this: 16 Gb / s - (16 Gb / s x 20%: 100%) = 12.8 Gb / s. Dividing the same 12.8 Gb / s by 6.4 GB / s, we get a real practical increase in the speed of 2 times between the 1 st and 2 nd PCI Express.

The third generation

The last and most actual update of this interface was released in 2010. The peak speed PCI-E x16 in this case increased to 64 Gb / s, and the maximum power of the graphic adapter without additional power supply in this case can be equal to 75 W.

Variants of configurations with several graphic accelerators in one PC. Their pros and cons

One of the most important innovations of this interface is the possibility of having several graphics adapters in the PCI-E x16 buses . Video cards are combined with each other and form, in effect, a single device. Their overall performance is summed up, and this makes it possible to increase the speed of the PC at times in the processing position of the output image. For solutions from NVidia, this mode is called SLI, and for graphics processors from AMD - CrossFire.

The future of this standard

PCI-E x16 slot In the foreseeable future certainly will not change. This will allow more efficient graphics cards to be used as part of legacy PCs and, through this, to carry out a phased upgrade of the computer system. Now the specifications of the 4th version of this method of data transmission are being worked out. For graphic adapters in this case, the maximum bandwidth of 128 Gb / s will be provided. This allows you to display the image on the monitor screen as "4K" or more.

Results

Whatever it was, and PCI-E x16 at the moment is a non-alternative graphics slot and interface. It will be relevant for quite a long time. Its parameters allow creating both entry-level computer systems and high-performance PCs with several accelerators. It is due to this flexibility and no significant changes are expected in this niche.