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How to connect 2 px 460 crossfire cards. What is AMD CrossFireX

In the article we looked at the technology of combining several video cards for their joint work from Nvidia - SLI (I advise you to familiarize yourself with it, because I will refer to it), now we will look at a similar technology from their competitors - AMD CrossFireX.

History of ATI CrossFire

In the late 90s, ATI was not doing very well - in 1999, Nvidia introduced two new generations in one year - Riva TNT2 and GeForce 256. 3dfx, the second competitor, in 1998 introduced SLI technology, which allows you to combine two Voodoo2 video cards together on one PC . But ATI was only able to present RAGE 128 (and a little later the overclocked PRO version), which had nothing innovative. Realizing that it would not be long before they left the video card market, they decided to copy the SLI technology from 3dfx and released a “dual-headed” ATI RAGE FURY MAXX video card, which included two RAGE 128 PRO GPUs. The technology itself for combining video chips was called MAXX (Multiple ASIC Technology), and was purely software: each of the GPUs completely prepares one frame, and when displayed on the screen, they alternate. In essence, it was the spitting image of AFR (Alternate Frame Rendering) technology, which is still used today.

But, however, the FURY MAXX video card simply had two GPUs; it was impossible to combine two video cards from ATI - in those days there was an AGP bus, and there was only one this port on motherboards. In 2004, the PCI Express bus was introduced, which made it possible to divide the lines - and therefore make several ports and connect several video cards. Nvidia took advantage of this by introducing the new SLI technology, and ATI, which changed the name MAXX to CrossFire.

There were enough differences between them then: to create CrossFire, you needed a so-called master card - it had an overlay chip inside, allowing you to receive data from the slave card and combine it pixel-by-pixel with the main card. The connection took place through a special DVI-DMS cable, and the monitor was connected through another DVI connector extending from the master card:

This was terribly inconvenient, and in the future ATI came to the same thing as Nvidia immediately - data is transmitted through a special bridge, and there is no such thing as master or slave anymore (and even further, AMD, which bought ATI, abandoned bridges altogether) . And if this first difference was a minus for ATI, then the second, on the contrary, is a plus: if in SLI you can combine video cards of only one series, then in the case of ATI, video cards can even be of different generations.

Subsequently, in 2008, AMD introduced Quad CrossFireX - a technology that allows you to combine up to four video cards together, and now the technology for combining video cards is called AMD CrossFireX (or CF for short).

Imaging algorithms using CF

The first algorithm is not new - it is also successfully used by Nvidia. It's called Slicing(Slicing), and consists in the fact that the frame is divided into two parts - one is processed by one video card, the other by another:


Moreover, the parts may not necessarily be the same: it all depends on the complexity of the scene, and the rendering areas for each video card may be different. This algorithm is poorly suited for games, because it is impossible to calculate the complexity of a frame in advance.

ATI/AMD came up with the second algorithm themselves. It's called (from the English tile - tile). The essence of the algorithm is that the entire frame is divided into “tiles” of 32x32 pixels each, and each video card prepares its half of the tiles in a checkerboard pattern:


The advantage of this method is that each of the two video cards will account for on average half the load, that is, there is no such thing as in Slicing, when one video card got the sky in the game and it prepared the frame in 5 ms, and the other got a bunch of textures of the ground, buildings, and so on further, and she prepared the frame in 20 ms: here each of the video cards got the sky, and the textures of the earth and other objects. But, as one would expect, there are also disadvantages: firstly, the most exact matching of the characteristics of the video cards is required: if in Slicing the frame can be divided proportionally to the performance of each GPU, then in Tiling the load is divided exactly in half, so the video cards must be completely identical. Secondly, the geometric load is not divided between the cards, but in games it is usually low and there are no problems with this.

The third algorithm AFR, common with Nvidia - each of the video cards prepares frames one by one:


The advantages are the same - no artifacts when rendering a frame, you can easily parallelize the load across 4 GPUs. Minus - all frames have different complexity, which can lead to jerky pictures at low fps.

And the last algorithm of “honest” CrossFire is SuperAA(super smoothing). The principle is similar to that of SLI AA - each video card smoothes the image with a certain step relative to the other, and then the resulting images are stitched together into one frame. However, there are still differences from SLI AA - in the case of Nvidia, MSAA anti-aliasing is used, in the case of AMD - SSAA (it gives a slightly better picture, but also requires more resources). Anti-aliasing modes from x8 to x14 are available (let me remind you that Nvidia has a maximum of x32).

In the case of laptops on AMD APUs, which include both a processor and integrated graphics, AMD was more cunning than Nvidia: if the laptop has discrete graphics from AMD, then it can be combined with integrated graphics Dual Graphics when both video cards are working (let me remind you that Nvidia has Optimus technology, which allows you to use either discrete graphics or integrated graphics, but not both). However, this method has its limitations: firstly, it only works with DirectX 10 and higher (in principle, taking into account the fact that games with DirectX 9 are old and undemanding by modern standards - CF is not needed there). Secondly, the difference in the performance of discrete and integrated video cards cannot be more than twofold, that is, combining the graphics integrated into the APU with some R9 M390, alas, will not work (again, here the integrated graphics are like the fifth wheel in a cart and will only get in the way, so AMD basically did the right thing).

System requirements for CrossFireX

Almost everything here is the same as for SLI from Nvidia (so I won’t rewrite the requirements a second time), but there is one important difference - there is no need for bridges to connect video cards at all (it’s funny - in the thousandth line, Nvidia not only did not abandon bridges for SLI - she introduced new, even faster ones), the CF controller is now located on the video card board itself, and data is transmitted via PCI-E. There are no other significant differences - video cards of the same series are still connected, the memory capacity is still limited to that of the weakest video card in DX 11 and is summed up in DX 12.

And the most important question is: does it make sense to do CF? Yes, it does. Everything is simple here - green fans can buy one GTX 1080 Ti, which will be enough for all modern games, so SLI is basically not needed for games. AMD has the most powerful graphics so far - the RX 580, which is generally at the level of the updated GTX 1060, and which is only enough for FHD (in 2K you will have to significantly reduce the settings, or play at 30-40 fps). So here CF makes sense - two RX 580 will allow you to play normally in 2K on ultra graphics settings.

“The life of trade and the death of traders” - this is what Bernard Shaw said about it. And he spoke about competition, without which a market economy is impossible.

In a recent review, we looked at NVIDIA SLI technology. As noted at the beginning of that article, we examined the first technology on the modern graphics market for parallel operation of several video cards in one gaming scene. And since there is the first, it means there will be a second, since competing companies cannot allow NVIDIA to monopolize the market in this area. As one would expect, the main competitor, the Canadian company ATI, put forward its counterweight to SLI in the form of its own CrossFire technology (the company is now owned by AMD, but the CrossFire brand has been retained in the form of ATI CrossFireX).

Development history and key features

The technology was announced at the international exhibition Computex 2005 in Taiwan.

So, ATI CrossFire technology was designed to enable the creation of very high-performance gaming systems. Let us outline the main tasks that ATI engineers set themselves: first of all, to maximize system performance in 3D applications, as well as improve image quality. At the same time, there was a need to maintain compatibility with all games and cover a wide range of graphics card models to work in the CrossFire system. The Canadians tried to use the positive experience from their past similar projects.

Let's remember, for example, ATI's first development in the field of multi-chip solutions - the ATI Rage Fury MAXX card:

In 1999, several manufacturers released new generation video cards. NVIDIA even did this twice: in the spring Riva TNT2, and in the fall - a completely new product GeForce 256. But ATI, unfortunately, apart from the fact that it belatedly offered RAGE 128 and announced an improved version of this chip RAGE 128 PRO, nothing sensationally revolutionary didn't. However, there are methods to improve your product without creating a new video chip. Once upon a time this path was paved by 3dfx, which included in Voodoo2 the ability to work in tandem with the same video card. We are talking about the well-known SLI (Scan Line Interleave) technology. This technology allows you to use two cards on the Voodoo2 chip or just two Voodoo2 chips on one board to render the game simultaneously. Each of the Voodoo2-based cards in this case calculates either even or odd lines of the frame displayed on the screen, as a result of which the performance of the video subsystem increased by more than one and a half times.

ATI also used a similar idea, unable to compete with new solutions from NVIDIA. As a solution, a technology codenamed Aurora was proposed, which later received the name MAXX (Multiple ASIC Technology). MAXX technology is a pure software solution that allows you to use two GPUs to do a shared job. In fact, the idea of ​​parallel data processing is being realized. Each of the GPUs completely forms one frame, and then the finished frames are displayed one by one on the monitor. The technology that allows two graphics chips installed on the same card to alternately display finished image frames on the screen is called Alternate Frame Rendering (AFR).

And so, presenting a new implementation of the idea of ​​parallel rendering of a 3D scene in 2005, we had to recall all the existing developments, improve them and supplement them with new capabilities. In addition, the shortcomings of competing solutions from the American company NVIDIA were taken into account.

Let's look at the key differences between ATI CrossFire and NVIDIA SLI. Let us immediately make a reservation that these differences took place in the past and are given only for historical reference and to reflect the progress of development of both technologies.

The most important difference between ATI technology was that to create a combination of two video cards, they must be of the same series, but not necessarily the same model, while in SLI technology both video cards had to be absolutely identical, almost up to the BIOS firmware version. This was extremely important, since various combinations are possible for Radeon cards, for example, X1600 PRO and X1650 XT, which gave users greater freedom of choice when upgrading.

To date, this advantage over SLI has been retained. Radeon HD3800 and HD4800 series video cards “get along” well in one system in various combinations. Moreover, both within the line (HD3850+HD3870) and between generations (HD3870+HD4850). Although the latter is not confirmed by the official compatibility table:

ATI engineers called the second significant advantage of CrossFire over SLI the independence of the technology from driver optimization. However, we waited for what was promised for more than three years (since May 31, 2005, when the official worldwide announcement of ATI CrossFire technology took place) and still did not arrive. According to the developers, their technology should work with all existing games, even those released before its implementation.

With game support, CrossFire is doing a little better than SLI, but, as practice shows, even today there are games that in no way respond to the appearance of a second video card in the system. It all comes down to the same driver optimization that users hate. We will look at game compatibility and performance gains later in this article.

But it was not without its drawbacks. In its original form, ATI CrossFire technology required the presence of a so-called Master card. Such cards had the prefix CrossFire Edition in their names. They are equipped with an overlay chip that receives information from the slave card and combines it pixel-by-pixel with the master card.

On top is the CrossFire Edition X850XT card, and below is the standard X850XT. Pay attention to the overlay chip located under the transparent cooler casing.

The two cards are connected using an external cable that connects the DVI output of a regular card to a special DMS connector on the CrossFire Edition card. And the partially processed frame from the first card is sent via DVI to the DMS input of the CrossFire Edition card. As a result, the work of the two video chips is summarized in the Compositing Engine chip.

This approach slightly restrained the spread of the technology, since Master cards were not as widespread in retail sales as their regular variants.

As noted above, this method of organizing a combination of two video cards is already outdated. Today, combining two or more video cards in CrossFire mode, as with SLI technology, requires the use of special connecting bridges.

The fact that both competing companies chose this particular hardware method of organizing the connection once again confirms its maximum efficiency and practicality. Consequently, CrossFire Edition video cards left store shelves forever.

An important aspect in promoting CrossFire technology to the market is that it is supported not only by AMD’s own chipsets, but also by the most popular chipsets from Intel, although this support is implemented at the software level. And with the advent of the P45 Express logic set, the technology has received great potential for use in the “Performance” class. The fact is that as the performance of video cards increases, the load on the PCI-e bus, which must ensure data exchange between the motherboard and the video card, increases. And, if in the case of one PCI-e video card the bus has 16 lanes, the so-called PCI-e x16, then in CrossFire mode mid-level motherboards can only provide PCI-e x8, which is clearly not enough for modern video cards. Starting with the P45 Express chipset, mid-range motherboards support PCI-e 2.0 with twice the bandwidth of version 1.0a. Previously, such a standard was only available on motherboards in the highest price range.

Imaging algorithms

Dividing the screen into several non-overlapping zones (Scissor, also known as Slicing).

This mode cannot be called new - it is what NVIDIA SLI uses. Here the top of the frame is shown by one card and the bottom by another. Interestingly, the border of the zones does not have to run in the middle of the frame and can be selected dynamically, based on the complexity of a particular part of the image - roughly speaking, there may be fewer objects (the sky) in the upper half than at the bottom, and then one of the accelerators will be idle, which can be compensated by increasing his area of ​​responsibility. The task of such dynamic balancing is non-trivial and requires scene analysis, which is not always convenient.

Advantages of the method:

  • divides both geometric and pixel load;
  • high degree of asynchronous operation of video chips;
  • the accelerator has complete control over its reporting area of ​​the result image.

Disadvantages of the method:

  • requires balancing of zones on the fly to evenly distribute the load;
  • there may be problems with smoothing at the junction of zones;
  • requires significant intervention in the driver and therefore there is a high probability of unexpected and incorrect operation of some applications.

SuperTiling mode - checkerboard alternation of calculated pixels

In this mode, the frame is divided into blocks (also called “quads”). This results in a total of 256 blocks per frame. Even blocks are calculated by one card, and odd blocks by another.

In principle, using this mode you can display all applications and games. ATI has set this mode as the default for 3D games. However, despite all the improvements, there are also negative features. The fact is that, despite each card displaying half of the image, the geometry has to be fully calculated on both cards. As a result, productivity growth is not what it could be. However, even with such shortcomings, modern and future games that heavily use pixel shaders will provide excellent performance in this mode. In general, the more the game uses shaders, the greater the increase will be in a given CrossFire mode.

Advantages of the method:

  • divides the pixel load exactly equally;
  • very precise load balancing between video chips;
  • can be used for new full-screen anti-aliasing techniques;
  • easy to use for applications and requires almost no modification of drivers, there is little chance of applications not working correctly.

Disadvantages of the method:

  • does not divide the geometric load and therefore requires a significant margin in geometric performance;
  • requires sufficiently synchronous operation of video cards and, accordingly, their maximum identity.

Alternate Frame Rendering

AFR mode is the fastest - in it, cards output frames one by one. Let's say the first map displays all odd scenes, and the second - all even ones. Unlike SuperTiling and Scissor modes, where both cards have to calculate the geometry for each scene, AFR mode allows each card to only do half the work because each map calculates geometry and shading only for its frames.

Advantages of the method:

  • divides both the pixel and geometric load, and the geometry is not duplicated on the bus - different video cards receive different sets of data;
  • the video card is fully responsible for its frame, no traces of joining, even in the case of complex processing, no restrictions on the method of constructing the frame.

Disadvantages of the method:

  • uneven frame rotation and load distribution;
  • Efficiency highly depends on the CPU and system, as well as on the nature of the scene and falls with increasing frames per second;
  • the problem is with a significant delay between the frame that is being shown to us and the frame that is currently being built.

The last disadvantage of this method does not allow it to gain global recognition among users and in some way slows down the spread of the entire multi-GPU technology as a whole (both SLI and CrossFire). The fact is that this image output method sometimes gives the effect of “microlags” - small jerks in games that do not depend on the load and speed of your system.

SuperAA mode

It is obvious that the greatest increase in speed from using CrossFire will be obtained by games, especially those that load the computer’s graphics subsystem. But what if one video card can handle the game just fine? What to do with the second one?

Especially for such cases, CrossFire has the ability to work to improve picture quality - the Super AA mode was developed for this purpose. Thus, gamers can take advantage of the potential power of CrossFire by using a new full-screen anti-aliasing method. With its help you can get the highest picture quality, which is not available on single video cards.

ATI DPP(PhysX)

Also, in March 2006, ATI introduced support for hardware physics acceleration with its video cards for games optimized for the Havok FX engine.

It was stated that acceleration of physics calculations will be supported by Radeon X1000 series graphics cards, and asymmetric configurations will also be supported, for example CrossFire for 3D rendering and an additional accelerator for physics calculations.

In addition, the possibility of using two different video cards for calculating physics has been announced. Unfortunately, the possibility of simultaneously using the resources of a powerful GPU for graphics and physics was not announced, as previously expected.

For GPU processing of physics, ATI plans to use a technology it calls DPP (data parallel processing), which allows a common set of instructions to be applied simultaneously to a large array of source data.

It was stated that the performance of ATI's solution would be superior to dedicated PhysX boards in many cases. Below are the proposed applications of the GPU as a physical accelerator.

Unfortunately, specific deadlines for the implementation of ATI physics acceleration software and hardware have not yet been announced; they will probably be announced in the near future, given NVIDIA's breakthrough in this direction with NVIDIA PhysX technology.

From history to modern times

To build a computer based on CrossFire you must have:

  • a motherboard with two or more PCI Express x16 slots with an AMD or Intel chipset of certain models;
  • powerful power supply;
  • video cards with CrossFire support.

A CrossFire system can be organized in two ways:

  • Internal connection - video cards are connected via a flexible bridge. The driver determines which of them will be the master card.
  • Software method - video cards are not connected in any way, data is exchanged via the PCI Express x16 bus, and their interaction is implemented using drivers. The disadvantage of this method is the loss in productivity up to 10-15% compared to the first method mentioned above.

As you may have guessed, the software method is used extremely rarely and mainly on not the newest low-power cards. Regarding the bridge connection, be careful. Unlike NVIDIA SLI, 2 bridges are used here and they must be connected correctly, usually on the side of the primary card (the monitor is connected to it) the bridge is marked with a smaller index, and on the slave side with a larger index, for example, “J1A” “J2A” or “J2” and “J3”, although other more or less understandable designations are also possible. Otherwise, the driver will not recognize the installed combination of video cards and will ask you to change the bridge configuration on the corresponding Catalyst Control Center page.

This is what the various options for connecting bridges for CrossFire look like.

CrossFire is enabled quite simply by checking the box in the Catalyst Control Center menu.

Triple CrossFire and QUAD CrossFireX

With the release of drivers version 8.3, ATI officially announced the availability of QUAD CrossFireX technology. However, it is only available for video cards of the HD 3800 generation and higher.

The word QUAD does not mean that combinations of only four video cards are possible. The same technology also includes Triple CrossFire - a combination of three video cards. What’s interesting is that there can physically be two video cards, but three video chips are used. For those who didn’t guess, we’ll explain - in this case, a combination of a regular video card and a video card with the suffix “X2” is used, which has 2 video chips. Here is an example of two video cards Radeon HD 3870 and HD 3870X2 in Triple CrossFire mode.

And here is the result of their joint activities using the example of the game S.T.A.L.K.E.R.: Shadow of Chernobyl.

As you can see, the game responds favorably to the addition of a third video chip. The performance increase of two HD 3870 video chips compared to one is 85%, which is very good. But adding a third accelerator increases performance by another 33%, which is also quite good.

The QUAD mode is activated in two ways: the first is by installing four video cards in a special motherboard based on the AMD chipset, the second is by installing two video cards with the “X2” suffix in any one that supports CrossFire mode. As practice shows, the first method is used extremely rarely due to the small number of motherboards for 4 video cards and the large number of problems with their connection. Much simpler and more expedient method number two. It’s clear that “X2” video cards belong to the TOP solutions, and a combination of two such video cards is even more so.

However, in this way we will get unprecedented video subsystem performance.

It becomes obvious that for such video cards, motherboard support for the PCI-e 2.0 x16 standard is not just desirable, but mandatory.

Note that the Radeon HD 3870X2 video cards, which are actually a CrossFire implementation of a pair of GPUs on one video card, used a switching chip that was far from perfect. Not only did it limit the video card to only support PCI-e 1.0a, but it also had high latency. But progress does not stand still and, starting with the Rdeon HD 4870X2 line, a new switching chip is used that is devoid of these shortcomings. Now the internal organization of CrossFire in the video card has become much better, as well as the interaction of the video card with the motherboard, now via the PCI-e 2.0 interface.

The path of CrossFire technology to the masses has been so long and thorny. What does it represent today? And today it is a rapidly developing technology, support for which is widespread thanks to Intel and AMD chipsets. The uniqueness of the technology is its flexibility and the ability to be built on various motherboards and processors, using Intel processors if a motherboard on an Intel chipset is used, or using AMD processors if a motherboard on an AMD chipset is used - in any case, users have a wide choice of components.

AMD, which suffered a fiasco during the confrontation between Radeon HD 2000 (HD 3000) and GeForse 8 generation video cards, in the new Radeon HD 4000 line has set a course for promoting its products not in the TOP league, but in the middle (middle) and so-called productive ( Performance) segments. In view of this, having a bundle of two medium-priced video cards is often more profitable than buying a competitor’s TOP products.

Pay attention to the fourth line from the top - this is the HD4870 video card in CrossFire. A very good result, considering the recommended cost of each card. However, this is just a synthetic test, albeit a very popular one, but it shows the potential of the technology when maximally optimized for the game. If you analyze the graph, you can see that the mid-segment video cards of the previous generation compete quite well with the “top” modern cards, but of course not alone.

ATI Hybrid CrossFireX. This technology is similar GeForce Boost.

Like the competing Californian company, it is designed to combine the power of a video chip built into the motherboard and a discrete video card.

To activate this technology, you will need a motherboard with a set of system logic from the AMD 780 line.

It is logical that using a video card more powerful than the Radeon HD 3470 is not advisable.

Much more interesting is the use of this technology in laptops, where in addition an idea similar to HybridPower is implemented (it’s a pity that this function is not available on desktop systems).

Now in laptops based on the AMD 780 chipset it is possible to combine the graphic power of a discrete video chip with long-lasting battery life, since the discrete chip is simply turned off when there is no load.

Using hybrid graphics from AMD gives the user complete and easy control over image output.

We have already examined the performance of such a solution in one of our reviews. Let's remember the results...

...and conclusions:

“As a result, from the graphs we see that the performance of a “hybrid” graphics system, as well as a separate integrated core, strongly depends on the speed of exchange with memory, which is carried out by the processor via the HyperTransport bus. Therefore, Phenom processors have a certain advantage, but there is not much difference from using a triple or quad-core processor.

Even if the Hybrid CrossFire system were able to catch up with the NVIDIA GeForce 8500GT DDR3 Sonic, then from the point of view of economy this option would be questionable, since the cost of more powerful processors is an order of magnitude more expensive than video cards. Therefore, the technology of combining an external video card with integrated graphics will be of more interest to users who usually use image output on three or four monitors, and sometimes they need to work with 3D.”

Practical Application

We have already tested Radeon video cards of various price ranges in CrossFire combination. Let's try to analyze these results and draw a conclusion about the feasibility of using this technology and its competitiveness.

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As is already clear from the title of the article, I bought a second video card and decided to take the opportunity to write a detailed article on this topic. Let's start from the beginning - what is Crossfire?

AMD CrossFireX ( originally called AMD CrossFire)- These are AMD technologies that allow you to combine several video cards into one system to increase computer performance in building 3D models and graphics. Of course, this technology is mainly intended for gamers, and not the poorest ones, since video cards and motherboards that support this function are at least in the middle price category. Although the price is not the only nuance that you need to know before purchasing, and now we will look at them.

What do you need to buy for a system unit to support CrossfireX?

So, first, I’ll list what we need to buy in order to build a full-fledged CrossFireX:

1) Motherboard;
2) Power supply;
3) Two or more video cards.

1) Motherboard (can be bought at OGO.ru). In principle, there is nothing complicated here, but before purchasing you need to carefully read the specifications on the manufacturer’s website, since important information is often hidden in stores. So, the first thing is technology support. CrossFireX, but there is one nuance here - the motherboard must have two full-fledged PCI-E x16 ports working in pairs in x16+x16 mode, but at least x8+x8 is possible (the difference will be a few percent, but still possible), although Ideally, it is better to use the first option. Stores very often do not disclose information that two of the three PCI-E x16 ports operate in x4 mode and, although possible for use, due to the weak use of the second video card, they become unsuitable for building CrossFireX. In this case, buying a second video card simply won’t pay for itself. At best, this will be written about in the “Additional Information” section, but as practice shows, this is not there. Therefore, do not be lazy to go to the manufacturer’s official website and look at the specifications for the motherboard that you are planning to buy, since here the manufacturer is obliged to indicate the real data. For example, here is the information on the Gigabyte website about my motherboard:

To make the search somewhat easier, there is already a list of chipsets that support the technology CrossFireX but this is only an approximate list; for final support, check the specifications on the manufacturer’s website.

for motherboards AMD AM3+:
AMD 990FX(x16+x16, PCI-E 2.0)
AMD 990X(x8+x8, PCI-E 2.0)
for motherboards AMD AM3:
AMD 890FX(x16+x16, PCI-E 2.0)
AMD 890GX(x8+x8, PCI-E 2.0)
AMD 790X(x8+x8, PCI-E 2.0)
AMD 790GX (x8+x8, PCI-E 2.0)
AMD 790FX(x16+x16, PCI-E 2.0)
for motherboards Intel LGA2011:
Intel X79 (x16+x16, PCI-E 3.0)
for motherboards under Intel LGA1366:
Intel X58 (x16+x16, PCI-E 2.0)
for motherboards Intel LGA1156:
Intel P55 (x8+x8, PCI-E 2.0)
*The choice of processor is also important here, CrossFireX is possible ONLY on Lynnfield processors (i5-7xx,i7-8xx). On Clarkdale processors (i3-5xx, i5-6xx, Pentium) - IMPOSSIBLE.
for motherboards under Intel LGA1155:
Intel P67 (x8+x8, PCI-E 2.0)
Intel Z68 (x8+x8, PCI-E 2.0)
*Please note that mat. boards based on Intel P55/P67/Z68 chipsets:
1) with an additional nForce 200 chip, they support the x16+x16 scheme
2) can only support the x16+x4 scheme
for motherboards AMD AM2:
AMD 580X (x16+x16, PCI-E 1.1)
AMD 790X (x8+x8, PCI-E 2.0)
AMD 790GX (x8+x8, PCI-E 2.0)
AMD 790FX(x16+x16, PCI-E 2.0)
for motherboards Intel LGA775:
Intel 975X (x8+x8, PCI-E 1.1)
Intel X38 (x16+x16, PCI-E 2.0)
Intel P45 (x8+x8, PCI-E 2.0)
Intel X48 (x16+x16, PCI-E 2.0)

2) Power supply (buy at OGO.ru). I have already written, so I won’t tell you in detail how this is done now. Just when choosing, now you need to take into account that there will be two video cards, so there must be wires to connect additional power to the video card, as well as the appropriate power to power the second video card (and this is from +100 to 350 W depending on the video card).

3) Video card (buy at OGO.ru). Everything is simple with her. First and most important, technology support is needed CrossFireX(always yours, Cap), and it manifests itself in a simple way: the video card must have a corresponding connector for connecting CrossFire bridge. Ideally, it is better to use two identical video cards. You can also combine different ones, but although the video cards will work completely synchronously, the more powerful video card will not be able to show its full capabilities, since it will have to adapt to the weaker card. There is no point in talking about the company; personally, when buying AMD cards, I try to buy Sapphire, since they are official partners (like Asus for Nvidia). According to the agreement with AMD, video card manufacturers are required to provide a bridge for connecting video cards to CrossFireX in the box with the video card. It looks like this:

How to connect and configure CrossFireX

I think that's enough theory - let's move on to practice, or rather to connection and configuration.

1) Install video cards into slots with x16 (or x8) bandwidth. To do this, you should refer to the instructions of the motherboard. On my card from Gigabyte, the manufacturer prudently marked these connectors with the corresponding inscriptions PCIEX16_1 and PCIEX16_2 (connectors that operate in x4 mode are marked PCIEX4_1 and PCIEX4_2).

2) Insert it so that the latch on the connector works. To reduce the load on the motherboard, it is better to screw the screws on the left side of the retaining panel on the rear wall of the case.

4) Start the system and log into Windows. I currently have the latest beta drivers installed (AMD Catalyst™ 14.1 Beta Driver), and after starting, the control panel itself detected the CrossFireX connection and offered to enable it, for which I should click the “Go” button:

If this does not happen for you, manually open the AMD Catalyst Control Center, open the “Performance” section (in the expanded menu view) and select AMD CrossFireX.

Mark here with a dot “ Enable AMD CrossFireX" and check the box "Enable AMD CrossFireX for applications that do not have an associated application profile." Click “Apply” below.

That's all. You can buy all the necessary components in the OGO.ru store. I hope you found this article useful, click one of the buttons below to tell your friends about it. Also subscribe to site updates by entering your e-mail in the field on the right.

AMD CrossFireX technology, the first implementations of which were released more than 10 years ago (in 2005), made it possible to combine the power of two, three or four video cards in one computer to improve gaming performance. Theoretically, such a solution sounds attractive, especially for those for whom the capabilities of a single GPU are not enough. It would seem that all you have to do is go to the store, buy a new video card, connect it to your PC and get an increase in FPS in games. But in reality, the situation is a little more complicated; this technology is not without a whole chain of limitations that need to be understood. This material will tell you how to connect two video cards in CrossFire.

Connecting two video cards via CrossFire: requirements

There are a number of limitations that need to be taken into account when creating a CrossFire configuration of two GPUs. These are the main conditions for two (or more) video cards to work in parallel.



It is important to remember that when connecting two video cards via CrossFire, their memory capacity does not add up. Each GPU uses video RAM only from its board, and its total practical volume is equal to smaller of two . Thus, when connecting 1 and 2 GB video cards, the result is not a bundle with 3 GB of total memory, but a configuration with 1 GB of usable space.

It’s the same with frequencies: when connecting overclocked and non-overclocked versions of one processor, the “sea principle” applies when the alignment is based on the slowest element. Therefore, in games that are not optimized for CrossFire (and there are many of them), the capabilities of the combination will be more modest than those of a PC with one video card installed.

CrossFire compatibility of video cards: table from AMD

AMD, the company that produces Radeon graphics processors, regularly publishes and updates tables that indicate which graphics cards can be combined in CrossFire. You can get acquainted with their most current version on the official website. Here is a Russified version of the official tables, the information in which is presented as of February 2016.

Compatibility table for R-series video cards

CrossFire compatibility of Radeon 5000-7000 series video cards

CrossFire compatibility of video cards 3000-5000 series

Connecting two video cards via CrossFire

If all conditions are met, you can proceed to creating the CrossFire configuration. To do this, you need to install video cards in the slots on the board, connect power cables to them (if any are required) and connect the cards with bridges. The connection occurs from the first board to the second, from the second to the third, etc. If there are two cards, you can use either one or two connectors: this will not affect the operation in any way. A number of video adapters (they are noted in the table) do not require bridges for connection. In this case, data exchange between them is carried out via the PCI-Express bus.

Two budget video cards in CrossFire without bridges

Once the cards are connected, the system can be started. Then you should update your video card drivers, go to the AMD Catalyst Control Center and in the “Performance” tab, check the “Enable AMD CrossFireX” checkbox.

Results

Connecting two video cards via CrossFire contributes to a significant increase in performance in compatible (adapted) games. Of course, performance does not increase twice, but by 80%, but this is also more effective than replacing the GPU with another one that has twice the number of computational elements. For example, a pair of Radeon HD 7770 (or R7 250X, which is the same thing) with 640 shader cores each will be faster than one HD 6930 equipped with 1280 processors.

However, in some cases such significant growth will not be achieved. Most games released before 2010 are very reluctant to be friends with CrossFire. And among the more modern ones, there are those in which the increase in performance will be insignificant. It is important to remember this before connecting two video cards with CrossFire bridges. This is especially true for owners of outdated video cards of previous generations. It’s very difficult to find a second HD5750 or 6750 new on sale, and if one is found somewhere in retail, it’s better to get a newer GPU for the same money. For example, instead of another 5750, which cost about $100 at the end of sales (it makes no sense to give the price in rubles, since the exchange rate has changed significantly over 4 years), for this money you can take

When choosing a video card from AMD, the user may notice the CrossFire option in the list of options. This is a special technology that was developed by AMD engineers with the goal of combining several video cards into one system. Thanks to the use of CrossFire technology, it is possible to extend the life of old video cards, as well as increase the maximum power of the system several times. But CrossFire technology has a lot of nuances that must be observed for it to work correctly and for video cards to perform to the maximum of their capabilities. In this article, let's look at the subtleties when setting up CrossFire and combining several video cards.

Table of contents:

What is required to connect two video cards via CrossFire

To combine two video cards into one, you will need not only their presence and two slots on the motherboard. There are a number of conditions that must be met to take advantage of CrossFire technology and unlock the potential of two GPUs. Before combining two AMD cards via CrossFire into one common performance element, make sure that the following components meet the necessary requirements.

. The motherboard must have at least two PCI-Express. It is important that the slots have maximum throughput. For modern motherboards this is x16. For now, pay close attention. Only if you have x16 bandwidth for both video cards connected to the motherboard will you be able to achieve maximum performance. Often, motherboards have one main x16 connector and several auxiliary connectors with lower bandwidth. It could be x8 or x4. Some video cards do not have a PCI-Express slot with x16 bandwidth at all, and all slots are x8.


Please note: To connect AMD video cards via CrossFire, you can also use connectors with x8 bandwidth or one x16 and the other x8. But this will reduce the overall performance of the combined array.

The throughput of the connectors is marked with a corresponding inscription next to them. If it is x16, it will be written PCIEX16_1, PCIEX16_2 and so on. If x8, then PCIEX8_1.

In addition to having two connectors on the motherboard for connecting video cards via CrossFire, it must support this functionality at the chip level. It is important to note here that not all chips support CrossFire, and it is better to check the fact of compatibility on the website of the motherboard manufacturer. It is also worth noting that only motherboards based on AMD and Intel chips work with CrossFire technology. If the motherboard is made on an Nvidia chip (a company that is a direct competitor to AMD), it definitely does not support the patented CrossFire technology. Please note: Motherboards that support CrossFire have this marking on the box.

. Ideally, it is better to combine two identical video cards - of the same series and from the same manufacturer - into an array via CrossFire. But this is not always possible, so on the AMD website, as well as on the websites of video card manufacturers, you can find detailed tables with the compatibility of certain graphics processors with each other. Important: If the cards are CrossFire compatible, but one of them is more powerful than the other, you should know that the more powerful model will not be able to fully operate. The cards will work at the level of two weak cards from this pair.

It is worth noting that video cards with CrossFire support always come with a bridge to connect them. It is a small wire with a corresponding logo and a connector on both sides.

Power unit. The video card is one of the main consumers. When there are two of them, and they work simultaneously, especially with the same x16 bandwidth, this is a very serious load on the power supply. You need to have the right power, and also take into account whether it has the required number of connectors to connect all the components.

Housing and cooling system. Another point that is often forgotten when wanting to build a computer assembly with two video cards connected via CrossFire is the presence of a good case. Video cards must not only fit into the unit along with other components, but it must also have a good ventilation system. It is wrong to think that the coolers on the video card itself are enough to cool the chip. The temperature in the case must be kept low, and when two video cards are running, it will be significantly higher than when one is running. Therefore, the case must be equipped with its own high-quality coolers to remove hot air.