AMD CrossFire technology accelerates graphics quality and performance by combining the processing power of multiple GPUs.
With AMD CrossFire technology, two or more discrete graphics cards can be configured to work together. You can also configure discrete GPUs to work alongside integrated GPUs using AMD Radeon™ Dual Graphics Technology. AMD Radeon Dual Graphics technology is based on AMD CrossFire technology and is only available on AMD APU-based systems.
Before you enable and configure AMD CrossFire technology, you must run the AMD CrossFire setup, which may require connecting a pair of video cards using an AMD CrossFire bridging cable. For more information about installing AMD CrossFire graphics cards, see your graphics card's user manual.
With AMD CrossFire support enabled, one GPU functions as the primary processor. Subsequently, graphics rendering tasks are distributed between this GPU and other processors to speed up image rendering on a separate display connected to the main GPU. Additional displays can be connected to the main GPU if it is running in extended desktop mode.
Note: If AMD CrossFire support is enabled or disabled, the Control Center application automatically restarts. AMD CrossFire is designed for applications running in full-screen mode. Displays not connected to host GPUs in an AMD CrossFire configuration are automatically disabled. For some configurations, you can optionally unlock support for displays connected to auxiliary GPUs.
Availability of AMD CrossFire pages and options may vary depending on specific graphics cards. The layout of the AMD CrossFire pages also depends on the currently used view:
- Standard view - AMD CrossFire page is in groups Performance And Games > Performance. If you are using an AMD FirePro™ graphics card, the page is in groups Performance And AMD FirePro > Performance.
- Advanced view - AMD CrossFire page is in groups Performance and Games. If you are using an AMD FirePro graphics card, the page is in groups Performance and AMD FirePro.
GPUs in AMD CrossFireX and AMD Radeon™ Dual Graphics configurations work together using one of four graphics rendering modes: Mosaic, Scissor Mode, Frame Alternate Rendering, and Super Anti-Aliasing.
The first three modes are focused on performance, while the super smoothing mode is focused on quality. Each mode uses a different way to distribute the workload across multiple GPUs when rendering 3D images. The AMD Catalyst™ display driver automatically selects the most optimal of three operating modes when launching a 3D application.
Tip: You can also improve image quality by selecting the super anti-aliasing mode (levels above 6×).
Mosaic In this mode, each processed frame is divided into a number of tiles arranged in a checkerboard pattern so that each of the two GPUs processes half of the tiles. Each tile is a 32x32 pixel square, so this method provides good workload distribution between GPUs, regardless of the rendered image displayed on the display, and without wasting software resources.
The advantage of mosaic mode is its ability to work with almost any 3D application. However, there are a small number of applications where tiled workload distribution does not provide optimal performance. In these special cases, the scissor mode can be used. Scissor Mode In this mode, each frame is divided into two sections, each of which is processed by one GPU. The ideal configuration is determined automatically for each application.
Although scissor mode is generally a less efficient way to distribute workload than mosaic mode, it can be more effective in some cases. This mode is supported by AMD CrossFireX technology for maximum compatibility and performance. Alternate Frame Rendering (AFR) In this mode, all even frames are rendered on one GPU, while all odd frames are rendered on another GPU. The rendered frames are sent from both GPUs to the compositing engine on the AMD CrossFireX Edition card, which then delivers them to the display. By allowing both GPUs to operate independently, AFR mode maximizes the performance of all available modes. This mode is also the only mode that allows you to simultaneously use all the processing power of both GPUs for vertex processing.
The main limitation of this mode is that it cannot be used in applications in which the appearance of the current frame depends on the data generated in previous frames, since the AFR mode involves the formation of successive frames on different GPUs. In such cases, use mosaic mode or scissor mode instead. Super Anti-Aliasing Anti-aliasing is a rendering technique designed to remove jagged edges, flicker, and pixelation that often occur in rendered 3D images. Instead of simply determining the color displayed for each pixel on the screen by sampling from one location at the center of the pixel, antialiasing takes samples at different locations on each pixel and mixes the resulting results to create the final color.
Most AMD GPUs use a technique known as multi-sample anti-aliasing (MSAA). This method samples 2, 4, or 6 programmable locations in each pixel and applies gamma-corrected blending of the samples to produce high-quality smooth polygon edges. The new AMD CrossFireX Super Anti-Aliasing mode leverages the GPU's programmable sampling capabilities to provide higher quality anti-aliasing on AMD CrossFireX systems.
In this case, each GPU renders the same frame with anti-aliasing enabled, but each GPU samples from a different location. Once both frame renderings are complete, the results are mixed in the AMD CrossFireX compositing engine. The resulting image is created from twice as many samples, so 4x and 6x antialiasing become 8x and 12x antialiasing, respectively.
Some textures, especially those with transparent areas, may exhibit aliasing that MSAA cannot correct. In these cases, another type of anti-aliasing called low-resolution anti-aliasing (SSAA) can be useful because it affects every pixel in the image. Although the process is typically slower than MSAA, the processing power of multiple GPUs can make SSAA practical.
When using SSAA, it first renders the scene at a higher resolution than the output resolution of the display, and then forces the resolution downsampling to match the display's resolution. This approach usually has two main drawbacks: it requires processing many more pixels than usual, which can have a big impact on performance, and it also results in the use of ordered lattice sampling, which is poorly suited for smoothing some types of jagged edges. AMD CrossFireX super anti-aliasing eliminates both of these shortcomings. This uses a second GPU to render the extra pixels needed for each frame, so there is little or no performance impact. It can also use a more efficient sampling model to provide better anti-aliasing of near-horizontal and near-vertical edges, resulting in higher overall image quality.
Two super anti-aliasing modes use a combination of MSAA and SSAA techniques to ensure maximum image quality. These modes not only use different multisampling locations for each GPU, but also slightly shift the pixel centers. Essentially, each GPU renders the image from different viewpoints spaced about half a pixel apart. The 10x and 14x super anti-aliasing modes work this way, combining 2x SSAA with 4x and 6x MSAA, respectively.
Both of these modes work in conjunction with anisotropic filtering (AF).
Users can enable super anti-aliasing modes using the Control Center app.
Note: Enabling super anti-aliasing modes (×8, ×10, ×12, ×14) disables multi-GPU (graphics processing unit) rendering, which is designed to improve performance to provide higher image quality.
Configuring AMD CrossFireX™ Hardware Settings
Use the AMD CrossFireX page to enable and configure AMD CrossFireX configurations that use AMD CrossFireX bridging cables. When AMD CrossFireX support is enabled, 3D games and applications automatically use AMD CrossFireX technology if the driver determines that using it is the optimal solution.
You can also configure super anti-aliasing mode for AMD CrossFireX using the 3D pages in the Control Center app.
Enabling AMD CrossFireX™
- Standard view - Performance And Games > Gaming performance.
- Expanded view - Performance and Games.
- Standard view - Performance And AMD FirePro > Graphics performance.
- Expanded view - Performance and AMD FirePro.
- Check the box Enable AMD CrossFireX .
- If necessary, click and drag the slider to unlock support for displays connected to auxiliary GPUs. Not all AMD CrossFireX configurations support unlocking displays connected to auxiliary GPUs.
- Click the Apply button.
Enabling AMD CrossFireX™
Enable AMD CrossFireX support to accelerate the quality and performance of 3D applications and games displayed on displays connected to the main GPU. When AMD CrossFire™ support is enabled, the best possible combination of GPUs to use is selected based on the current hardware configuration.
Note: If AMD CrossFireX support is enabled, Control Center automatically restarts. AMD CrossFireX is designed for applications running in full screen mode.
AMD Radeon™ dual-GPU graphics cards are powered by AMD CrossFireX technology. As a result, AMD CrossFireX support is always enabled for these boards.
- Go to the AMD CrossFireX page located in the groups below.
- Standard view - Performance And Games > Gaming performance.
- Expanded view - Performance and Games.
If you are using an AMD FirePro™ graphics card, you can navigate to the page using the groups below.
- Standard view - Performance And AMD FirePro > Graphics performance.
- Expanded view - Performance and AMD FirePro.
- If necessary, use the desktop selection menu at the top of the page to select the desktop associated with the GPU to use as your primary desktop.
- Check the box Enable AMD CrossFireX.As of Windows® 8.1, AMD CrossFireX support is enabled by default only for applications and games with a standard AMD profile or a custom application profile. To enable AMD CrossFireX for all games and applications - even those that do not have an application profile - select Enable AMD CrossFireX for applications without a profile.
- If necessary, click and drag the slider to unlock support for displays connected to auxiliary GPUs. Not all AMD CrossFireX configurations support unlocking displays connected to auxiliary GPUs. Note: For optimal performance when running 3D applications, connect all displays to the main GPU and (if necessary) unlock displays connected to the secondary GPU.
- Click the Apply button.
AMD CrossFireX is enabled and AMD CrossFireX automatically uses the best combination of GPUs for your system. Only displays connected to the primary GPU are available for use (additional displays must be running in extended desktop mode). Displays that are not included in the AMD CrossFireX configuration are also available for use. Displays connected to auxiliary GPUs remain usable only if support is unlocked.
If other GPU combinations are available, you may choose to use a different combination.
Note: If there are problems with your current AMD CrossFireX configuration, diagnostic information will be displayed at the bottom of the page.
Selecting GPU Combinations for AMD CrossFireX™
If your system has more than two graphics processing units (GPUs) that support AMD CrossFireX, you can select a specific combination of GPUs to use.
Note: When you change the GPU combination that is used for AMD CrossFireX, the Control Center application automatically restarts.
- Go to the AMD CrossFireX page located in the groups below.
- Standard view - Performance And Games > Gaming performance.
- Expanded view - Performance and Games.
If you are using an AMD FirePro™ graphics card, you can navigate to the page using the groups below.
- Standard view - Performance And AMD FirePro > Graphics performance.
- Expanded view - Performance and AMD FirePro.
- From the GPU combinations drop-down list, select the combination to use. Each list option lists the number of GPUs that support AMD CrossFireX and the adapter index of the primary GPU, followed by one or more secondary GPUs.
Note: If there are problems with the selected combination, diagnostic information will be displayed at the bottom of the page. - Click the Apply button.
The selected GPU combination is used for AMD CrossFireX.
Show or hide the AMD CrossFireX™ logo
When AMD CrossFireX support is enabled, you can choose to display the AMD CrossFireX logo for 3D applications and games running in full screen mode. This logo appears in the upper right corner of the screen and indicates that AMD CrossFireX support is enabled. When AMD CrossFireX support is disabled, the logo is not displayed.
Additionally, for AMD FirePro™ boards, the logo is also displayed for applications running in windowed mode.
- Right-click the Control Center logo on the Windows® taskbar (notification area).
- From the menu that appears, select the graphics card associated with the primary GPU for the AMD CrossFireX configuration, specify AMD CrossFireX Options and select Show CrossFireX status icon (if applicable) to display the AMD CrossFireX logo when AMD CrossFireX support is enabled. To always hide the logo even when AMD CrossFireX support is enabled, clear the check box.
Unlocking displays on secondary GPUs for AMD CrossFireX™
If your system supports displays directly connected to the secondary GPU in AMD CrossFireX, you can unlock support for the number of displays you plan to use.
Note: When you change the number of displays supported by the secondary GPU in the AMD CrossFireX group, the Control Center application automatically restarts.
- Go to the AMD CrossFireX page, located in the groups below:
- Standard view - Performance And Games > Gaming performance.
- Expanded view - Performance and Games.
If you are using an AMD FirePro™ graphics card, you can access the page using the groups below:
- Standard view - Performance And AMD FirePro > Graphics performance.
- Expanded view - Performance and AMD FirePro.
- Make sure AMD CrossFireX is enabled.
- Click and drag the slider to unlock support for displays connected to auxiliary GPUs.
Note: For optimal performance when running 3D applications, connect all displays to the primary GPU and (if necessary) unlock displays connected to the secondary GPU. - Click the Apply button.
AMD CrossFire™ Troubleshooting Tips
Below are solutions for common AMD CrossFire issues. For more information, visit the AMD CrossFire web page at www.amd.com.
Change Motherboard BIOS Settings Some motherboards may have a system BIOS setting that allows you to switch between single and dual PCIe® slot support. By default, one slot can be supported. Refer to your motherboard manual for information on how to enable dual PCIe slot support. Using graphics cards with different amounts of memory Some AMD CrossFire configurations may use graphics cards with different amounts of memory; However, after enabling AMD CrossFire, the computer must be rebooted. This will force AMD CrossFire to reduce the memory on the graphics card with more memory to match the memory on the graphics card with less memory.
When you click the Disable AMD CrossFire button, you will be prompted to restart your computer to restore the original amount of graphics memory, or continue with the reduced amount of memory. Swap Cards Recommended If the primary graphics card is not inserted into the primary PCIe slot, a message may appear advising you to swap graphics cards. Although AMD CrossFire may be enabled in this case, rearranging the graphics cards in your computer may improve system performance.
To find out which PCIe slot is the primary slot, see your motherboard documentation. 3D client is active AMD CrossFire cannot be enabled while a 3D application or game is running, or a video such as a DVD movie is playing.
Close all open 3D applications, games, and movie applications, and then enable AMD CrossFire. AMD CrossFire is currently unavailable This error occurred because the AMD CrossFire system did not correctly detect the graphics hardware or there was a software issue.
- Check that the graphics cards are installed correctly.
- Check that the connection cable is connected correctly.
- Close any running 3D applications.
- Reinstall the Control Center software and drivers.
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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 video cards of 1 and 2 GB, the result is not a bundle with 3 GB of total memory, but a configuration with 1 GB of usable space.
The same is true 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 into slots on the board, connect power cables to them (if 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, the performance does not double, 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 parameter 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 deliver 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.
Avid gamers have probably come across or at least heard about technologies called SLI and Crossfire, which are usually referred to as the graphics system of a computer or laptop. In most cases, such terms apply more to stationary systems (this will be discussed a little later). However, sometimes for normal computer operation you will need to know how to disable Crossfire or SLI when such modes are not used. This is what we will talk about now.
SLI and Crossfire: general concepts
It’s probably worth starting with the fact that, from the point of view of modern computer technologies, SLI and Crossfire are specialized modes that support the installation of two or more video cards on a computer.
In stationary systems, two independent video adapters are simply inserted into special slots located on the motherboard. Sometimes you can come across a situation where the motherboard already has an integrated graphics chipset, so to speak, “sewn” into the board, and another one is installed in parallel with it.
Now we will dwell on both modes in a little more detail, and at the same time we will look at how to disable Crossfire (SLI) using several simple methods if necessary, especially since both modes are practically the same in operating technology.
What is SLI?
SLI technology, which involves installing multiple graphics adapters in a system, was developed by nVidia and involves the use of cards only from this manufacturer.
In principle, this mode can be called a kind of conditional electronic adapter that connects two video adapters, allowing them to combine their capabilities into one.
What is Crossfire?
Crossfire is a complete analogy of SLI technology, but the authorship of this development belongs to the no less famous AMD corporation.
An interesting fact is that, as practice shows, combining two or more AMD video cards in Crossfire is much cheaper than using an SLI bridge when installing nVidia cards. In addition, nVidia technology does not allow installing such bundles on all motherboards in a row. But if we consider the question of how to disable SLI-Crossfire Dual Graphics, the solution in both cases will be the same. But first, let's look at some features of their use.
Features of connecting video cards in SLI and Crossfire modes
Firstly, every user of a computer system must clearly understand that connecting two or more graphics adapters to the motherboard is possible only in cases where the motherboard itself supports this feature.
For example, to use the SLI mode, the board must have the appropriate markings, otherwise, no matter how much you try to install two cards on it, they will not work together. The same applies to the simultaneous use of a discrete and integrated adapter. Here you will have to be content with only one of them.
Secondly, you should pay attention to the fact that to work in conjunction with SLI technology, you can install only video cards based on the same chips (for example, nVidia GTX 970 and 980 series, Titan series chipsets or two identical GT cards, etc. .). Please note: a combination of 9600 GT and 9800 GT will not work.
It's a different matter when Radeon cards are used. Here you can use “multi-chip” configurations, for example, Radeon 2600 and 1950. Very often, R9 series cards are used to increase graphics system performance. Indeed, such pairs allow you to use maximum capabilities for games with Full HD or 2k resolution. Some users use such combinations to increase the overall frequency of the storyboard, say, to achieve more than 80 fps (frames per second).
Thirdly, do not forget that for SLI cards a special adapter must be used, which must be supplied either with the card or with the motherboard. Without it, the two cards will again not work together.
Myths about using Dual Graphics mode to increase graphics performance
Some naive users install two cards to increase performance, believing that it will double (two cards on board). It's a delusion. The increase in productivity, as practice shows, rarely exceeds 20-30%.
In addition, this indicator is calculated based on a weaker card. For example, if we have 8 GB of memory on one card and 2 GB on the other, whatever one may say, the user will receive only 2 GB at the output. The same applies to installing two cards, say, with 4 GB of memory each. The output will remain the same 4 GB.
One more point: if one card is MSI and the other is EVGA, the total performance will be calculated based on the one with the lowest frequencies. So, as we see, there’s no point in flattering yourself.
How to disable SLI/Crossfire using the simplest method?
Now let's move on directly to the process of disabling these modes. Probably every user understands that the question “how to disable Crossfire or SLI mode” comes down to not using a second graphics adapter in the system. And, as is already clear, the simplest solution is to simply remove one of the cards from the slot on the motherboard, which applies to desktop computers.
But even on modern ultrabooks you can install additional equipment, in particular the same video adapters that, in principle, can use the Crossfire mode. How to disable one of the cards on a laptop? As easy as pie. The methods described below are suitable for both desktop computer terminals and laptops.
How to disable SLI (Crossfire) mode for a discrete adapter via BIOS?
To disable both modes, you can use the BIOS settings. Login is done by pressing the Del, F2, F12, etc. keys (it all depends on the BIOS version and developer).
Here we are interested in the tab containing the configuration called Onboard, Integrated Devices, etc. We enter the parameters and set the mode to Disabled (sometimes Off). That's all.
You can go to the Advanced section, where the settings of the mode itself will be indicated if you are using discrete rather than integrated adapters.
Using Device Manager
Now let's see how to disable Crossfire AMD or SLI nVidia using standard Windows tools. To do this, you need to go to the standard “Device Manager”. This is done either through the “Control Panel”, or through “Administration”, or using the devmgmt.msc command.
Here you need to go to the video adapters section, where the installed devices will be indicated. In this case, as in all other situations, the question of how to disable SLI-Crossfire comes down to making one of the cards inaccessible. Select the card to disable and right-click to open the properties menu, where there is a button to disable the device. You can use a similar command directly from the context menu. After this, you won’t even have to reboot the system.
Disabling modes using “native” utilities
Despite the simplicity of the described methods, it is best (and safer) to use “native” utilities for setting up and managing graphics adapters, which are installed automatically when installing the appropriate drivers, or installed additionally.
For nVidia cards, you can use GeForce SLI Profile Tool, PhysX, Riva Tuner, etc. For AMD chipsets, utilities like ATI Tray Tool or ATI Catalyst Control Center and others will be useful. Their use is simpler, so much so that you don’t even have to go through the system configuration or BIOS to change this or that parameter. If you look into it, this solution to the problem we are considering (how to disable Crossfire/SLI) will be more effective, and it will even eliminate the occurrence of conflicts between installed equipment (unfortunately, this also happens).
Instead of an afterword: should I disable dual graphics mode?
It remains to add a few words about the advisability of using such modes. Actually, the answer to the question: “How to disable Crossfire (SLI)?”, I think, is already clear. As for installing two or more video cards in one system and using them simultaneously, there are quite a lot of conflicting opinions. The fact is that you may not get much of a performance boost, and hardware conflicts are not excluded.
Of course, if the system does not use its graphics capabilities to the maximum, you need to disable these modes, because the simultaneous operation of two cards can lead to severe overheating of the computer, double power consumption by the graphics system (after all, two cards are installed), as well as the inoperability of some games, the program code of which is simply does not support such modes or is not fully adapted to their use.
In addition, it is not recommended to include bundles in the form of budget cards or mid-range adapters. It’s better to buy one more powerful one instead of two of these. Productivity will be much higher and there will be fewer problems. And in terms of money, this option is often preferable.
However, if you look at it, it is sometimes possible to use such modes, but in situations where two cards are not used, it is recommended to disable one of them, and for this you need to use special software designed to manage all the parameters of graphics adapters. And such a shutdown is carried out, as they say, in one click.
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
At the end of the 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 fact, 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 point 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 up to four video cards to be combined 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 is 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 has. 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.
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