When we talk about the PCI Express (PCI-E) bus, perhaps the first thing that sets it apart from other similar solutions is its efficiency. Thanks to this modern bus, computer performance increases and graphics quality improves.

For many years, the PCI (Peripheral Component Interconnect) bus was used to connect the video card to the motherboard, in addition to this, it was also used to connect some other devices, such as network and sound card.

This is what these slots look like:

PCI-Express was effectively the next generation of the PCI bus, offering improved functionality and performance. It uses a serial connection in which there are several lines, each of which leads to a corresponding device, i.e. Each peripheral device gets its own line, which increases the overall performance of the computer.

PCI-Express supports hot plugging, consumes less energy than its predecessors, and controls the integrity of transmitted data. In addition, it is compatible with PCI drivers– tires. Another remarkable feature of this bus is its scalability, i.e. pci express card connects and works in any slot similar or larger bandwidth. In all likelihood, this feature will ensure its use for years to come.

The traditional PCI slot type was good enough for basic audio/video functions. With the AGP bus, the scheme for working with multimedia data has improved, and the quality of audio/video data has increased accordingly. It wasn't long before advances in processor microarchitecture began to demonstrate even more clearly the slowness of the PCI bus, which made the fastest and newest computer models of that time literally barely drag themselves.

PCI-E Bus Characteristics and Bandwidth

It can have from one bidirectional connection line x1, to x32 (32 lines). The line operates on a point-to-point basis. Modern versions provide much greater bandwidth compared to their predecessors. x16 can be used to connect a video card, and x1 and x2 can be used to connect regular cards.

Here's what the x1 and pci express x16 slots look like:

PCI-E
Number of lines x1 x2 x4 x8 x16 x32
Bandwidth 500 MB/s 1000 MB/s 2000 MB/s 4000 MB/s 8000 MB/s 16000 MB/s

PCI-E versions and compatibility

When it comes to computers, any mention of versions is associated with compatibility issues. And like any other modern technology, PCI-E is constantly being developed and upgraded. The latest available version is pci express 3.0, but development of the PCI-E bus version 4.0 is already underway, which should appear around 2015 (pci express 2.0 is almost outdated).
Take a look at the following PCI-E compatibility chart.
Versions PCI-E 3.0 2.0 1.1
Total Bandwidth
(X16) 32 GB/s 16 GB/s 8 GB/s
Data transfer rate 8.0 GT/s 5.0 GT/s 2.5 GT/s

The PCI-E version has no effect on the functionality of the card. Most distinctive feature of this interface is its forward and backward compatibility, which makes it secure and capable of synchronization with many card variants, regardless of the interface version. That is, you can insert a second or third version card into a PCI-Express slot of the first version and it will work, although with some loss of performance. In the same way, you can install a PCI-Express card of the first version in the PCI-E slot of the third version. Currently, all modern video card models from NVIDIA and AMD are compatible with this bus.

And this for a snack:

I have been asked this question more than once, so now I will try to answer it as clearly and briefly as possible. To do this, I will provide pictures of the PCI Express and PCI expansion slots on the motherboard for a clearer understanding and, of course, I will indicate the main differences in the characteristics, i.e. .e. very soon you will find out what these interfaces are and what they look like.

So, first, let's briefly answer the question, what exactly is PCI Express and PCI?

What is PCI Express and PCI?

PCI is a computer parallel input/output bus for connecting peripheral devices to the computer motherboard. PCI is used to connect: video cards, sound cards, network cards, TV tuners and other devices. The PCI interface is outdated, so you probably won’t be able to find, for example, a modern video card that connects via PCI.

PCI Express(PCIe or PCI-E) is a computer serial input/output bus for connecting peripheral devices to a computer's motherboard. Those. this already uses a bidirectional serial connection, which can have several lines (x1, x2, x4, x8, x12, x16 and x32) the more such lines, the higher the bandwidth of the PCI-E bus. The PCI Express interface is used to connect devices such as video cards, sound cards, network cards, SSD drives and others.

There are several versions of the PCI-E interface: 1.0, 2.0 and 3.0 (version 4.0 will be released soon). Designated this interface usually like this PCI-E 3.0 x16, which means PCI Express 3.0 version with 16 lanes.

If we talk about whether, for example, a video card that has a PCI-E 3.0 interface will work on a motherboard that only supports PCI-E 2.0 or 1.0, the developers say that everything will work, just of course keep in mind that the bandwidth will be limited by possibilities motherboard. Therefore, in this case, overpay for a video card with more new version PCI Express I think is not worth it ( if only for the future, i.e. Are you planning to purchase a new motherboard with PCI-E 3.0?). Also, and vice versa, let’s say your motherboard supports version PCI Express 3.0, and your video card supports version 1.0, then this configuration should also work, but only with PCI-E 1.0 capabilities, i.e. There is no limitation here, since the video card in this case will work at the limit of its capabilities.

Differences between PCI Express and PCI

The main difference in characteristics is, of course, throughput; for PCI Express it is much higher, for example, PCI at 66 MHz has a throughput of 266 MB/sec, and PCI-E 3.0 (x16) 32 Gb/s.

Externally, the interfaces are also different, so connecting, for example, a PCI Express video card to a PCI expansion slot will not work. PCI Express interfaces with different numbers of lanes are also different, I will now show all this in pictures.

PCI Express and PCI expansion slots on motherboards

PCI and AGP slots

PCI-E x1, PCI-E x16 and PCI slots

The physical layer of the interface allows for both electrical and optical implementation. The basic electrical interface connection (1x) consists of two differential low-voltage signal pairs - transmit (signals PETp0, PETn0) and receive (PERp0, PERn0). The interface uses DC isolation of transmitters and receivers, which ensures compatibility of components regardless of component manufacturing technology and eliminates some signal transmission problems. Self-synchronizing coding is used for transmission, which allows achieving high transmission rates. Basic speed - 2.5 Gbit/s “raw” data (after 8B/10B encoding) in each direction, more is planned in the future high speeds. To scale throughput, it is possible to aggregate signal lines (lanes, signal pairs in the electrical interface), by the same number in both directions. The specification considers connection options of 1, 2, 4, 8, 12, 16 and 32 lines (denoted as x1, x2, x4, x8, x12, x16 and x32); The transmitted data between them is distributed byte by byte. In each of the lines, self-synchronization is performed independently, so that the carryover phenomenon (the scourge of parallel interfaces) is absent. In this way, speeds of up to 32×2.5 = 80 Gbit/s are achievable, which roughly corresponds to a peak speed of 8 GB/s. During hardware initialization, each connection negotiates the number of lines and transmission speed; negotiation is performed at a low level without any programmatic involvement. The agreed connection parameters are valid for the entire duration of subsequent work.

Providing hot plugging at the PCI Express physical layer does not require any additional hardware costs, since the point-to-point connection does not involve “extra” participants. Safe switching of signals is not required; the capabilities of the connected device do not in any way affect the operating modes of other devices.

The small number of interface signal pins gives greater freedom in choosing PCI Express design implementations:

• connection of components within the board;
• slots and expansion cards in PC/AT and ATX designs;
• internal and external expansion cards for mobile PCs;
• small-sized input/output modules for servers and communication equipment;
• modules for industrial computers;
• detachable connection of “daughter” cards (mezannin interface);
• cable connections of blocks.

For expansion cards in PC/AT and ATX designs, different modifications of the PCI Express connector-slot are provided, differing in the number of pairs of signal lines (x1, x4, x8, x16) and, accordingly, in size (see the figure below). At the same time, cards with a connector of the same size or smaller can be installed in larger slots (this is called Up-plugging). However, the opposite option (Downplugging) - a large card into a smaller slot - is mechanically impossible (in PCI/PCI-X it is possible). As shown above, the smallest PCI Express variant provides the throughput of a standard PCI bus.

The pin assignments of PCI Express slots are shown in the table below.

The set of PCI Express interface signals is small:

• PETp0, PETn0… PETp15, PETn15 — outputs of signal pair transmitters 0…15;
• PERp0, PERn0... PERp15, PERn15 — receiver inputs;
• REFCLK+ and REFCLK - 100 MHz reference frequency signals;
• PERST# — card reset signal;
• WAKE# — “wake-up” signal (from the card);
• PRSNT1#, PRSNT2# - card connection/disconnection detection signals for the hot plug system. On the map, these circuits are connected to each other, and for PRSNT2# the contact with the highest number is selected. This allows you to more accurately track the moments of connection and disconnection (in case of tilting the card). To determine the number of lines of a connected card, these lines are not used - the line capacity is determined automatically when a connection is established (during the training procedure).

Additionally, the slot contains optional SMBus bus signals (SMB_CLK and SMB_DATA) and JTAG interface signals (TCLK, TDI, TDO, TMS, TRST#).

Power is supplied to the cards via the following buses:

• +3.3V — main power supply +3 V at current up to 9 A;
• +12V — main power supply +12 V at a current of up to 0.5/2.1/4.4A for slots x1/x4, x8/x16, respectively;
• +3.3Vaux - additional power, current up to 375 mA in systems capable of waking up to a signal from the card and up to 20 mA in non-wakeable systems.

Table. PCI Express slots

For mobile computers PCMCIA introduced the ExpressCard design (see the following figure), for which two interfaces are output to the system connector: PCI Express (1x) and USB 2.0. ExpressCard modules are more compact than previous PCMCIA cards (PC Card and CardBus); There are two modifications available that differ in width: ExpressCard/34 (34×75×5 mm) and ExpressCard/54 (54×75×5 mm). The thickness of the modules is only 5 mm, but, if required, longer modules may have thickenings in parts that extend beyond the dimensions of the computer case (beyond 75 mm from the edge of the connector). Like legacy PCIMCIA cards, ExpressCards are user-accessible and hot-pluggable.

For internal maps expansion of notebook PCs, the Mini PCI Express design has been introduced (see figure below), the format of which is derived from Mini PCI Type IIIA. By reducing the number of pins, the card width is reduced to 30 mm, so that instead of one Mini PCI card you can fit a pair of Mini PCI Express cards. In addition to PCI Express, the card connector (see table below) contains serial bus interfaces USB 2.0 (USB_D+ and USB_D-) and SMBus (SMB_CLK and SMB_DATA), power supply +3.3 V (750 mA main and 250 mA additional) and +1 .5 V (375 mA). The PCI Express interface itself (x1) occupies only 6 pins (transmitter outputs PETp0 and PETn0, receiver inputs PERp0 and PERn0, as well as 100 MHz reference frequency signals REFCLK+ and REFCLK-. PERST# signal - card reset, WAKE# signal - “wake up” (from the card) LED_Wxxx# signals are used to control the status LEDs.

Table. Mini PCI Express connectors

The PCI Express interface conveniently accommodates input/output and network interface modules for servers and rack-mount communication devices. Such modules can be quite compact (2U height does not cause problems with connector placement), while the interface performance is sufficient even for such critical modules as Fiber Channel, Gigabit Ethernet (GbE), 10GbE.

The PCI Express interface is also accepted for industrial computers, for which there are PICMG 3.4 specifications (small-sized designs for x1, x2 and x4), as well as designs in the Compact PCI format.

The PCI Express interface also exists in a cable version for cable connections of units located at a short distance from each other. For example, via PCI Express you can connect docking stations to notebook PCs. The ability to output a system-level interface outside the computer case from PCI Express predecessors was supported only by the ISA bus, and then only at low communication speeds (at frequencies up to 5 MHz). Of the new system-level serial interfaces, InfiniBand also has this capability. The presence of a cable version of a high-performance system-level interface can allow us to move away from the traditional computer layout, in which all components that require intensive exchange with the computer core are concentrated in the system unit.

1. Hello! Please explain the difference in throughput between the PCI Express 3.0 x16 and PCI Express 2.0 x16 interface. Nowadays there are still motherboards with PCI Express 2.0 x16 interface on sale. I'm with I will lose a lot in video performance if I install new video card interfacePCI Express 3.0 on a computer with motherboard, where there is only a connectorPCI-E 2.0? I think that I will lose, because the totalbaud rate for PCI Express 2.0 it is - 16 GB/s, and totalPCI Express 3.0 has twice the data transfer speed - 32 GB/s.
2. Hello! I have a computer with a powerful, but not new Intel processor Core i7 2700K and a motherboard with a PCI Express 2.0 slot. Tell me, if I buy a new PCI Express 3.0 video card, this video card will work twice as slow as if I had a motherboard with a connector PCI Express 3.0? So it's time for me to change my computer?
3. Please answer this question. My motherboard has two connectors: PCI Express 3.0 and PCI Express 2.0, but in the connector PCI Express 3.0 new video card PCI Express 3.0 does not fit, the radiator is in the way south bridge. If I install a video cardPCI-E 3.0 in slot PCI-E 2.0, then my video card will perform worse than if it were installed in a PCI Express 3.0 slot?
4. Hello, I want to buy a slightly used motherboard from a friend for two thousand rubles. Three years ago he bought it for 7,000 rubles, but what confuses me is that it has a slot for an interface video card PCI-E 2.0, and I have a video cardPCI-E 3.0. Will my graphics card run at full capacity on this motherboard or not?

Hello friends! Today on sale you can find motherboards with a connector for installing PCI Express 2.0 x16 video cards, and PCI Express 3.0 x16. The same can be said about graphics adapters; there are video cards with an interface on sale PCI-E 3.0, as well as PCI-E 2.0. If you look at the official characteristics of the PCI Express 3.0 x16 and PCI Express 2.0 x16 interfaces, you will find out that the total data transfer speed of PCI Express 2.0 is- 16 GB/s, and PCI Express 3.0 is twice as large -32 GB/s. I won’t go deep into the specifics of how these interfaces work and will simply tell you that there is such a big difference indata transfer speed is visible only in theory, but in practice it is very small.If you read articles on this topic on the Internet, thenyou will come to the conclusion that modern PCI Express 3.0 graphics cards operate at the same speed in PCI Express 3.0 x16 and PCI Express 2.0 x16 slots and difference in throughputbetween PCI-E 3.0 x16 and PCI-E 2.0 x16 is only 1-2% loss in video card performance. That is, it doesn’t matter which slot you install the video card in, PCI-E 3.0 or PCI-E 2.0, everything will work the same.

But unfortunately, all these articles were written in 2013 and 2014 and at that time there were no games like Far Cry Primal, Battlefield 1 and other new products that appeared in 2016. Also released in 2016 family GPUs NVIDIA 10 series, for example video cards GeForce GTX 1050 and GeForce GTX 1050 Ti and even GTX 1060. My experiments with new games and new video cards showed that the PCI-E 3.0 interface has an advantage overPCI-E 2.0 is no longer 1-2%, but on average 6-7%. What's interesting is if the video card is of a lower class than GeForce GTX 1050 , then the percentage is less (2-3%) , and if on the contrary, then more - 9-13%.

So, in my experiment I used a video card GeForce GTX 1050 PCI-E 3.0 interface and motherboard with connectors PCI Express 3.0 x16 and PCI Express 2.0 x16.

N Graphics settings in games are maximum everywhere.

1. Game FAR CRY PRIMAL. Interface PCI-E 3.0 showed an advantage over PCI-E 2.0, since always higher by 4-5 frames, which is approximately the percentage 4 % %.
2. Battlefield game 1.The gap between PCI-E 3.0 and PCI-E 2.0 was 8-10 frames , which in percentage terms is approximately 9%.
3. Rise of the Tomb Raider. Advantage of PCI-E 3.0 averages 9- 10 fps or 9%.
4. The Witcher. The advantage of PCI-E 3.0 was 3%.
5. Grand Theft Auto V. The advantage of PCI-E 3.0 is 5 fps or 5%.

That is, there is still a difference in throughput between the PCI-E 3.0 x16 and PCI-E 2.0 x16 interfaces and it is not in favor PCI-E 2.0. So I wouldn't buy at at the moment motherboard with one PCI-E 2.0 connector.

One of my friends bought a used motherboard for three thousand rubles. Yes, it was once sophisticated and cost about ten thousand rubles, it has a lot of connectors SATA III and USB 3.0, also 8 slots for RAM, it supports RAID technology and others, but it is built on an outdated chipset and the video card slot on it is PCI Express 2.0! In my opinion, it would be better to buy. Why?

It may well happen that in a year or two the latest video cards will only work in the connector PCI Express 3.0 x16 , and your motherboard will have an obsolete connector that is no longer used by manufacturers PCI Express 2.0 x16 . You buy a new video card, but it will refuse to work in the old connector. Personally, I have already encountered many times that the video card PCI-E 3.0 did not run on the motherboard. board with connector PCI-E 2.0, and Even updating the motherboard BIOS did not help.I also dealt with video cardsPCI-E 2.0 x16, which refused to work on older motherboards with the interface PCI-E 1.0 x16, although everywhere they write about backward compatibility.Cases when a PCI Express 3.0 x16 video card did not start on motherboards withPCI Express 1.0 x16, even more.

Well, don’t forget about the appearance of the interface this year PCI Express 4.0. In this case, PCI Express 3.0 will become obsolete.

"Manhunt1908“The motherboard’s support for the new PCI Express v.3.0 standard is actually not its competitive advantage.” Basically, it turns out that PCI Express 3.0 does not actually have any real advantages, and it will not increase the speed in modern games. then no one needs or is interested in it anymore, there is no growth, which means it sucks, but in addition to the gaming functions of the PCI Express v.3.0 standard, it also has other functions, in particular USB 3.0 directly depends on the motherboard with PCI Express support function v.3.0, they themselves say that, Well, the presence of two or four USB 3.0 ports in a computer, by today’s standards, is simply necessary, 3.0 is much faster than 2.0, many have tested this in practice. Whatever one may say, a motherboard with PCI Express v. 3.0 is needed, a lot latest technologies are tied to this particular standard. It’s unlikely that anyone would refuse to have such a long list on board their motherboard, given below!
SupremeFX IV
Perfect Sound
This motherboard boasts a high-quality audio system based on the built-in SupremeFX IV sound card, noted on printed circuit board special line. Capacitive capacitors and electromagnetic shielding contribute to highest quality sound. Additionally, the SupremeFX IV includes a dedicated headphone amplifier.

GameFirst II
The GameFirst II function based on cFos Traffic Shaping technology will help set the priority of Internet channel use by various applications. Having received maximum priority, online games will work as quickly as possible, without annoying “lags,” and other online applications that have a low priority for using the Internet channel will not interfere with them. There is a user-friendly ROG-style GUI to access this feature.

Gigabit Ethernet Controller
Intel network controllers are famous for their stable and efficient operation with low CPU load.

mPCIe Combo Adapter and Wi-Fi/Bluetooth 4.0 Controller
To save the main expansion slots, this motherboard is equipped with a special additional slot with an mPCIe Combo adapter, to which you can connect devices with mSATA interfaces (for example, a solid-state drive) and mPCIe (wireless Wi-Fi adapters, 3G/4G, GPS, etc.). Moreover, the package already includes an mPCIe card with support for Wi-Fi 802.11 a/b/g/n and Bluetooth 4.0.

Fusion Thermo Cooling System
To cool the power system elements on this motherboard, a special ROG Fusion Thermo cooler is used, which consists of a copper water block, massive radiators and a heat pipe. Thus, it can be used both as part of a liquid cooling system and for conventional cooling with fans. > Find out more
ROG Connect

Interface for overclocking and configuration ROG Connect
Using the ROG Connect function, you can monitor the status of your computer and configure its settings in real time using a laptop by connecting the latter to the main system via a USB cable.

Extreme Engine Digi+ II
Highly efficient digital system nutrition
The Extreme Engine Digi+ II power management system delivers highly efficient operation thanks to variable frequency pulse width modulation of the processor and memory digital voltage regulators. It also uses high quality capacitors from Japanese manufacturers. A reliable and powerful power supply system is the key to successful operation of a computer in overclocking mode!

ROG CPU-Z
New face of a famous utility
ROG CPU-Z is a customized version of the famous information utility from CPUID. It provides the same functionality and accuracy of system data as the original, but has a unique Republic of Gamers style interface. With ROG CPU-Z you can get full information about the processor and some other components of your computer.

Multi-GPU technologies
LucidLogix Virtu MVP
High speed in graphics applications
LucidLogix Virtu MVP technology is software for Windows 7, which implements automatic switching between the graphics core built into the processor and a discrete video card. By putting the discrete video card into sleep mode at times when its resources are not needed, energy savings are achieved, the noise level from the computer is reduced and the internal temperature is reduced system unit, which contributes to a more favorable operating mode of all components. In addition, you can use the integrated graphics core to accelerate the main graphics card, which allows you to increase performance by 60% (based on 3DMark Vantage tests). It is also worth noting that this technology Fully compatible with Intel Quick Sync 2.0 video transcoding feature.