For the few who care, AMD has confirmed that its Radeon RX 5700 series graphics cards do not support CrossFire, the company’s multi-GPU technology. Here’s the statement that TechPowerUp received directly from AMD:
Radeon RX 5700 Series GPU’s support CrossFire in ‘Explicit’ multi-GPU mode when running a DX12 or Vulkan game that supports multiple GPU’s. The older ‘implicit’ mode used by legacy DX9/11/OpenGL titles is not supported.
This should not affect most enthusiasts, as the interest in multi-GPU continues to wane even further. AMD is probably better off devoting its time to something else, but TechPowerUp notes that NVIDIA did bring back NVLink for its RTX 2070 SUPER.
AMD, responding to our question on CrossFire compatibility clarified that AMD dropped CrossFire support for “Navi” in favor of DirectX 12 and Vulkan “explicit” multi-GPU mode. The older “implicit” multi-GPU mode – CrossFire – used by DirectX 11, DirectX 9, and OpenGL games is not supported. The AMD statement follows.