Monday, October 26th 2015
DirectX 12 Mixed Multi-GPU: It Works, For Now
One of biggest features of DirectX 12 is its asymmetric multi-GPU that lets you mix and match GPUs from across brands, as long as they support a consistent feature-level (Direct3D 12_0, in case of "Ashes of the Singularity"). It's not enough that you have two DirectX 12 GPUs, you need DirectX 12 applications to make use of your contraption. Don't expect your older DirectX 11 games to run faster with a DirectX 12 mixed multi-GPU. Anandtech put Microsoft's claims to the test by building a multi-GPU setup using a Radeon R9 Fury X, and a GeForce GTX 980 Ti. Some interesting conclusions were drawn.
To begin with, yes, alternate-frame rendering, the most common multi-GPU method, works. There were genuine >50% performance uplifts, but nowhere of the kind you could expect from proprietary multi-GPU configurations such as SLI or CrossFire. Second, what card you use as the primary card, impacts performance. Anandtech found a configuration in which the R9 Fury X was primary (i.e. the display plugged to it), and the GTX 980 Ti secondary, to be slightly faster than a configuration in which the GTX 980 Ti was the primary card. Mixing and matching different GPUs from the same vendor (eg: a GTX 980 Ti and a GTX TITAN X) also works. The best part? Anandtech found no stability issues in mix-matching an R9 Fury X and a GTX 980 Ti. It also remains to be seen how long this industry-standard utopia lasts, and whether GPU vendors find it at odds with their commercial interests. Multi-GPU optimization is something both AMD and NVIDIA spend a lot of resources on. It remains to be seen how much of those resources they'll be willing to put on a standardized multi-GPU tech, and away from their own SLI/CrossFire fiefdoms. Read the insightful article from the source link below.
Source:
AnandTech
To begin with, yes, alternate-frame rendering, the most common multi-GPU method, works. There were genuine >50% performance uplifts, but nowhere of the kind you could expect from proprietary multi-GPU configurations such as SLI or CrossFire. Second, what card you use as the primary card, impacts performance. Anandtech found a configuration in which the R9 Fury X was primary (i.e. the display plugged to it), and the GTX 980 Ti secondary, to be slightly faster than a configuration in which the GTX 980 Ti was the primary card. Mixing and matching different GPUs from the same vendor (eg: a GTX 980 Ti and a GTX TITAN X) also works. The best part? Anandtech found no stability issues in mix-matching an R9 Fury X and a GTX 980 Ti. It also remains to be seen how long this industry-standard utopia lasts, and whether GPU vendors find it at odds with their commercial interests. Multi-GPU optimization is something both AMD and NVIDIA spend a lot of resources on. It remains to be seen how much of those resources they'll be willing to put on a standardized multi-GPU tech, and away from their own SLI/CrossFire fiefdoms. Read the insightful article from the source link below.
55 Comments on DirectX 12 Mixed Multi-GPU: It Works, For Now
It's a nice experiment but it comes across as impractical for your average title.
And we're talking about an alpha game with never used DX features on immature drivers. I'm pretty sure any testing is for shits and giggles b/c it's interesting. Not b/c it has any new information. We already know that Nvidia cards bog down under heavy load more compared to AMD. There's no new info except that the DX12 craziness actually works.
Fury X + Fury shows 66% gain over Fury X by itself
Fury X + 980Ti shows 75% gain.
This is proprietary tech vs a DX12 feature aka agnostic and the agnostic option is kicking the crap out of said proprietary solution.
This crap scales decently well (we already know xfire/sli is all over the place) and the slower cards lost. Big surprise. Two fury Xs would win. Big surprise.
It has been said that in DX12 would have many functions that were previously Driver (AMD or Nvidia) would be transferred to the API (Dx12), it shows that Microsoft will have more freedom on the use and operation of hardware in DX12, which is simply FANTASTIC, it means more access to the Hardware and less dependence on drivers.