DX12 Enables Cross-SLI Between AMD and Nvidia GPUs

DX12 will allegedly enable mixed configurations of AMD and Nvidia GPUs to piece of work together through the explicit asynchronous multi-GPU characteristic. This was revealed in a recent commodity by Tom's Hardware, in which the website claimed through some of its own sources that Microsoft's upcoming DirectX 12 API will enable cross-vendor multi-GPU configurations.

AMD Nvidia Feature This essentially ways that users should be able to run AMD Radeon graphics cards with Nvidia GeForce graphics cards at the same fourth dimension in a Cantankerous-SLI sort of configuration. Co-ordinate to Tom's Hardwre's source this is possible because DX12 treats all the graphics processors in the system as one big graphics processor. And then your Intel HD integrated graphics or AMD Radeon R7 integrated graphics + any detached GPU or GPUs you lot have in the arrangement will essentially be addressed and treated every bit i monolithic graphics processing unit.

This likewise means that if y'all have two 4GB GPUs y'all will in fact get 8GB of usable graphics memory instead of just 4GB like y'all exercise correct at present. This is because instead of tasking each GPU with rendering a whole frame on its ain, each GPU would actually return different parts of the same frame. Which in turn negates the need of having to mirror the resource in the two separate retentivity pools of the cards. This is the limitation behind the alternate frame rendering technique used today that prevents developers from addressing the two divide memory pools as a larger unmarried pool of graphics memory.

DX12 Enables Cross-SLI Between AMD and Nvidia GPUs

I know what you lot're thinking, all of this sounds fantastic and wonderful but is information technology realistic ? Now that's the ane million dollar question. Before we reply that question nosotros have to familiarize ourselves with the real-earth technical and non-technical hurdles that stand up in forepart of this vision.

Let's take a step dorsum and examine Mantle, AMD'southward own depression level API. Drapery actually supports explicit asynchronous multi-GPU control. In fact this feature was used in Civilization : Across Globe, which is i of the more recent Mantle titles. The developers of Firaxis used explicit asynchronous multi-GPU to implement split frame rendering (SFR) for CrossfireX support under Curtain. While the DX11 implementation of CrossfireX used the standard alternate frame rendering (AFR) technique.

Mantle Explicit Asynchronous multi-GPU Here's the catch, while explicit control of multi-GPU configurations is fantastic information technology also requires a huge corporeality of effort from the programmer to not but ensure that multi-GPU configurations work equally intended but also that there's a sufficient operation advantage over AFR. So what it essentially does is have some of the responsibility away from the hardware vendor and the commuter team and put it in the hands of the game programmer.

A practiced SFR implementation requires a considerable corporeality of skill and talent but if done correct can yield noticeable improvements over AFR, especially in reducing input-latency. It's a unlike type of technical claiming for each game to implement SFR. Some game engines and game genres are more than suitable for information technology while others aren't. For case in a plow based strategy game input-latency wouldn't exist as important equally it is in a fast paced FPS game.

Apart from the technical challenge of splitting each frame and assigning the parts to different graphics processors in the arrangement, which can be extremely challenging. Especially if the different graphics processors in the system accept different performance characteristics ( loftier-end discrete GPU vs an integrated GPU ). There'southward also the challenge of dealing with unlike GPU architectures that back up dissimilar sets of features. Of a sudden the developer not will have to figure out how to split each frame and the performance required for each role, but will likewise have to brand sure that the elements of each part of the frame are compatible with the GPU assigned to information technology.

But put it's a huge technical challenge that requires years of experience and out of the box thinking by the developer. I can certainly imagine leading edge developers such as Crytek and the technical guys at Dice attempting to use this explicit asynchronous multi-GPU feature with great success. But it will be limited to GPUs based on the same compages, at to the lowest degree initially.
Of course all of these challenges that we discussed have to be addressed before we even attempt to debate the politics involved of an Nvidia GPU working with an AMD GPU in tandem. Hardware vendors like to keep tight control over how their hardware is used and the overall user experience. While it's "technically" possible to mix and match GPUs cross-vendor with low level APIs such as Mantle and DX12, it's simply not realistic and can never exist in an official chapters.

The real, 18-carat benefit of explicit command over the graphics subsystem lies somewhere else. Where this characteristic will truly shine I believe is in utilizing the integrated graphics which is sitting idle in every single gaming arrangement with a discrete GPU. We should see game developers take advantage of integrated GPUs in handling things such as AI and physics. Peculiarly in processors that support unified memory such every bit AMD's Kaveri and Carrizo and allegedly Intel's Skylake. It'll take some time just nosotros'll get there.