▷ What is amd crossfire how does it work?

AMD CrossFire is an expression that has accompanied us for many years, since it is very common to see the mention of this technology when we are going to buy a new motherboard or a new graphics card. What is AMD CrossFire and what is its function? We explain it to you in this article. Let's start!

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What is AMD CrossFire and how does it work?

AMD CrossFire refers to a brand name for Advanced Micro Devices' multi-GPU system. Currently, up to four GPUs can be used on a single PC, with the ability to improve graphics performance by up to 4x that of a single GPU. CrossFire is AMD's equivalent to Nvidia's SLI, although the two technologies have some differences.

This technology was originally introduced to the public in 2005. The setup required a compatible motherboard along with a pair of Radeon PCI Express ATI Crossfire Ready graphics cards. There were a couple of compatible cards that included the Radeon X800s X850s, X1900s, and X1800s series. All of these cards come in a regular and Master edition. The user would have to buy a Master card and then it should be paired with a regular card from the same series. The Master card came with a dongle that functioned as the link between the two cards, which would send the incomplete images between the two cards and eventually be sent to the monitor for further processing. The second generation no longer requires a card called "Master."

AMD CrossFire-compatible graphics cards and motherboards

CrossFire technology is an evolution to further enhance its capabilities by connecting two or more different GPUs for better combined performance. The best thing about Crossfire X is that it doesn't slow down the clock speed of the fastest GPU when run alongside other graphics processors. So for example if you combine a Radeon 7950 and a 7870 in the Crossfire setup it will work fine. This differs from Crossfire and SLI, which require you to pair the same GPUs.

To build a system with CrossFire support, you first need a motherboard that supports this technology. CrossFire is currently usable on all AMD X470, AMD B450, AMD X399, Intel Z370, Intel H370, and Intel X299 motherboards. CrossFire requires a minimum of PCI Express x4 slots to function, although it is best if they are PCI Express x8 or PCI Express x16.

The Radeon R9 290 and R9 290X graphics cards introduced the fourth generation of CrossFire, which no longer has bridging ports. Instead, they use XDMA to open a direct communication channel between multiple GPUs in a system, which operates on the same PCI Express bus that is used by AMD Radeon graphics cards.

PCI Express 3.0 lanes provide up to 17.5 times greater bandwidth (15, 754 GB / s for a slot of 16) compared to current external bridges (900 MB / s), making the use of a physical bridge unnecessary. XDMA was selected for higher GPU interconnect bandwidth demands generated by AMD Eyefinity and, more recently, by 4K resolution monitors. The bandwidth of the XDMA open data channel is fully dynamic, scales with the demands of the game being played, and adapts to advanced user settings such as vertical sync.

AMD Hybrid CrossFire is another version of this technology that allows you to use integrated graphics and low-end discrete graphics in CrossFire mode, so you can take advantage of the processing capabilities of the integrated graphics chip in the processor together with the graphics card.

Drawbacks of AMD CrossFire

The most notable drawback of CrossFire is that the video memory of the two graphics cards does not add up, just like with Nvidia's SLI. This is because the two cards do not share the memory data, so both must have in their memory all the data they need to work. Another drawback is that the model with the largest amount of memory will be downgraded to match that of the card with the lowest memory. In this way, if an 8 GB card was paired with the 4GB version of the same card, the 8GB version will be downgraded to 4 GB, which will mean missing some of the potential of the first one.

AMD CrossFire also shares other drawbacks with Nvidia's SLI. This technology is highly dependent on optimization by video game developers, so that if not implemented correctly, performance may be even lower than that obtained by running the game with a single card. That is why it is far from doubling the performance of many games by running two cards.

The other big drawback is the large amount of energy that two jumbo graphics cards consume and all the heat they generate, especially in the case of AMD since its architecture tends to consume and heat up more than Nvidia's.

These drawbacks mean AMD has decided to reduce its support for CrossFire technology . AMD's newer graphics cards, the Radeon RX Vega, are no longer compatible with this technology, without AMD offering a substitute. With this, AMD has decided to save resources that can be dedicated to other more important tasks, such as improving its own graphics architecture.

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