The Guru of 3D published a review on the Ashes of Singularity: DX12 Benchmark II with Explicit Multi-GPU mode tested A quote from the article:

Stardock and Oxide Games have renewed their Beta with an updated DirectX 12 benchmark, an upgrade to Ashes of the Singularity Benchmark I, released in Fall of 2015. We take a look at this new build in relation towards PC gaming graphics card performance with AMD and NVIDIA graphics cards. In this article we'll look at single card performance.

However, we'll also have a look at a new DX12 related feature called explicit multi-GPU. You can now insert an additional video card into your PC and increase performance. Explicit Multi-GPU allows gamers to use an AMD card and an Nvidia card in the same system.

Ashes of the Singularity takes place in a post-technological singularity universe in which humans have begun to colonize the stars. Now, they face a foe that threatens to annihilate them, the Substrate, a race of machines that seeks to control the same worlds that humanity is claiming. Beta 2 includes a new DirectX 12 benchmark developed by Oxide Games as well as explicit support for new DirectX 12 features such as multiple GPUs and Asynchronous compute.

 Ashes of Singularity: DX12 Benchmark II with Explicit Multi-GPU mode tested @ Guru3D