An AMD coup
To say these benchmark results are unexpected would be an understatement. While it's true that AMD has been banging the DX12 drum for a while, its performance in Ashes is astonishing. AMD's cheaper, older, and less efficient GPU is able to almost match and at one point beat Nvidia's top-of-the-line graphics card. AMD performance boosts reach almost 70 percent under DX12. On the flip side, Nvidia's performance is distinctly odd, with its GPU dropping in performance under DX12 even when more CPU cores are thrown at it. The question is why?
Did AMD manage to pull off some sort of crazy-optimised driver coup? Perhaps, but it’s unlikely. It's well known that Nvidia has more software development resources at its disposal, and while AMD's work with Mantle and Vulkan will have helped, it's more likely that AMD has the underlying changes behind DX12 to thank. Since the 600-series of GPUs in 2012, Nvidia has been at the top of the GPU performance pile, mostly in games that use DX10 or 11. DX11 is an API that requires a lot of optimisation at the driver level, and clearly Nvidia's work in doing so has paid off over the past few years. Even now, with the Ashes benchmark, you can see just how good its DX11 driver is.
Optimising for DX12 is a trickier beast. It gives developers far more control over how its resources are used and allocated, which may have rendered much of Nvidia's work in DX11 obsolete. Or perhaps this really is the result of earlier hardware decisions, with Nvidia choosing to optimise for DX11 with a focus on serial scheduling and pre-empting as AMD looks to the future with massively parallel processing.
