▷ Nvidia sli vs amd crossfire

If you want to create the fastest gaming PC in the world, you will want to put as many graphics cards as possible inside, since this component is the main responsible for the performance of video games. For this, both Nvidia and AMD have the Nvidia SLI vs AMD CrossFire technologies respectively, which will allow you to use several graphics cards on the same PC.

Index of contents

SLI vs CrossFire

AMD's CrossFire and Nvidia's SLI are the technologies that the two graphics card giants use to make their own GPUs work together on a single system. Both technologies originally required the use of a flat cable to connect the multiple graphics cards together, but while with Nvidia's GeForce cards this is still the case, AMD's Radeon GPUs can now function without such restrictions and communicate happily over the Interface. PCIe 3.0.

Both CrossFire and SLI are two different technologies that pursue the same goal.

Nvidia's SLI still requires bridging, and for your high-end cards you need the high-bandwidth SLI jumper connector for maximum benefit. With the new GeForce RTX 20, a further step has been taken, with the inclusion of a bridge based on the NVLink interface.

The way the two technologies represent the graphics of the game is quite consistent. Both use split frame rendering (SFR) or alternate frame rendering (AFR). The first means that the GPUs share the representation of each frame with each other, while the more common AFR method, each GPU shares a part of the scene of each frame.

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Nvidia's SLI technology is more restrictive in terms of which graphics cards you can use in a multi-GPU array. Both cards must have the exact same GPU for the Interface to work. They can be from different manufacturers, Asus and Gigabyte cards can work together, but they must use the same chip. One GTX 1070 needs another GTX 1070 to work together. As for CrossFire, you can use different GPUs from the same generation of graphics cards. So you can put an RX 580 together with an RX 570, although it is not recommended to put together very different performance cards.

Very uneven performance in different games and require a lot of optimization work

The eternal promise of both SLI and CrossFire has been to deliver the highest possible performance, taking multiple high-end graphics cards and creating very powerful gaming equipment. Choose a single affordable primary GPU, then buy another later, possibly for less than the price of the first, and get the same level of performance that you would get from a more expensive alternative. This works really well in games highly optimized for these technologies.

For example, a single GeForce GTX 680 card scores 3354 in 3DMark 11 using the Extreme preset. That's a pretty high score, but it jumped to just 6463 after we added a second card and enabled SLI. The Metro 2033 benchmark with a single GeForce GTX 680 card offers 54.33 frames per second in high settings at a resolution of 2560 by 1600. Pairing two of the same cards running on SLI got 93 fps.

A pair of Radeon HD 7970 graphics cards showed a similar performance improvement when using CrossFire. A single Radeon HD 7970 scored 3321 on 3DMark 11 and 58.67 fps on Metro 2033 using the same settings as GeForce cards. With CrossFire enabled, the Radeons' 3DMark 11 and Metro 2033 scores jumped to 6413 and 99.33 fps, respectively.

SLI vs CrossFire
	GeForce GTX 680	GeForce GTX 680 SLI	Radeon HD 7970	Radeon HD 7970 CrossFire
3DMark 11	3354 points	6463 points	3321 points	6413 points
Metro 2033	54.33 FPS	93 FPS	58.67 FPS	99.33 FPS

But this has never been fully accomplished, as SLI and CrossFire have long been technologies that offer diminishing returns on your investment. It's very rare to get double the performance in a game by adding a second GPU, and the performance boost gets noticeably smaller the more graphics cards are added to an array. And that's if the developer of a game even bothers to implement SLI or CrossFire support. This is the most important problem facing multi-GPU technologies and arguably the reason for its decline, and its potentially imminent death. With the increased cost of game development, it is difficult for AMD or Nvidia to encourage developers to take an active interest.

DirectX 12 offers native multi GPU support

Nvidia is currently offering SLI support only on its most powerful cards, while AMD is neglecting its CrossFire technology, but in favor of DirectX 12 API-based multi-GPU support. Having a specific multi-GPU abstraction layer built into DX12 means it should be simpler for developers to support more than one graphics card on a single PC. AMD has already shown that the latter can work: two Radeon RX 580s, when combined, can deliver the same level of performance as the high-end Radeon RX Vega 64.

But this only happens in games that explicitly offer multi-GPU compatibility with DX12 mGPUs, like Deus Ex: Mankind Divided, Rise of the Tomb Raider, and Hitman. There aren't a lot of games using DirectX 12 yet, and only a few of them deliberately implement the mGPU abstraction layer.

So, with Nvidia and AMD seemingly backing down in terms of explicit SLI and CrossFire support, it seems like the days of their bespoke multi-GPU technologies are numbered. The future of video games goes through DirectX 12 and its subsequent revisions, so it is expected that more and more games will include the mGPU abstraction layer of this API.

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This ends our special article on the differences between AMD CrossFire and Nvidia SLI, remember to share the post on social media so that it can help more users.

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