With the introduction of the new RX 5700 graphics cards, there was a question about their functionality: Is it compatible with CrossFire? In other words, would the Radeon RX 5700 and RX 5700XT support multi-GPU configurations? AMD responded quickly.
The RX 5700 Series GPUs support CrossFire in “explicit” multi-GPU mode when running a DX12 or Vulcan game that supports multiple GPUs. The old ‘implicit’ mode used by older DX9/11/OpenGL titles is not supported.
AMD is not going to support multi-GPU
What does this mean? Firstly this means that CrossFire is not compatible with the Navi RX 5700 series. PC players should not expect to run Navi in a multi-GPU configuration, at least not in the rare use of “explicit” multi-GPU in an occasional DirectX 12 or Vulcan title. This multi-GPU support is still rare with modern game titles, meaning that in most cases multi-GPU support with Navi is not possible.
Multi-GPU support has become unreliable in recent years, with less supported games. In addition, a single, more powerful graphics card is almost always better than combining two smaller graphics cards in SLI, CrossFire, or another multi-GPU configuration. This is one of the reasons why Nvidia has removed SLI/NVLink compatibility from its low-end Pascal and Turing.
While AMD’s lack of implicit CrossFire compatibility with the Navi series graphics cards may be disappointing to some, it’s hard to see that a multi-GPU configuration of the RX 5700 or RX 5700XT might be worth recommending to PC gamers considering the prospects.