During its Build conference yesterday, Microsoft revealed that its next-gen graphics API offers enhanced support for accelerating performance with multiple GPUs. Dubbed DirectX 12 Multiadapter, this capability gives developers explicit control over GPU resources. It works with not only traditional CrossFire and SLI setups, which team multiple discrete graphics cards, but also with hybrid configurations that combine discrete and integrated GPUs.
According to Direct3D development lead Max McMullen, who presented a Build session on graphics performance, DX12's Multiadapter mojo lets developers generate and execute commands in parallel on multiple GPUs, complete with independent memory management for each one. Those GPUs can collaborate on rendering the same frame or do different kinds of work in parallel.
McMullen showcased the benefits for a hybrid configuration using the Unreal Engine 4 Elemental demo. Splitting the workload between unnamed Nvidia discrete and Intel integrated GPUs raised the frame rate from 35.9 FPS to 39.7 FPS versus only targeting the Nvidia chip. In that example, the integrated GPU was relegated to handling some of the post-processing effects.
A more impressive Multiadapter demo aired during yesterday's Build keynote. This one used a custom Square Enix Witch Chapter 0 [cry] scene designed to push DX12 to its limits, and the footage has already made its way to YouTube. Behold:
Four GeForce GTX Titan X graphics cards were required to run the demo in real time, which means we probably won't see graphics that good in games anytime soon. DirectX 12's ability to share workloads across different multi-GPU configurations looks very promising, though, especially since it doesn't require a high-end setup with multiple cards.