It's finally happened. AMD have launched their new graphics API, Mantle, to the public and you can pick it up right now in the new Catalyst 14.1 beta driver update. O bviously there are caveats. The first is that it's a beta driver so don't expect it to be rock-solid no matter what the situation - I've already encountered some glitches in a CrossFireX rig that I didn't see in a single GPU setup.
The biggest caveat though is that only AMD GPU-owners need apply, and then only those with Graphics Core Next architecture in their cards. That means all HD 77XX and above, and all R7 and above, will be able to support the new API.
Essentially the new application programming interface (API) is designed to be a low-level language that devs can utilise to get as close to the graphics hardware as possible. “Here's a way to give developers access as close as possible to the metal,” AMD Senior Director Neil Robison told me in January. “Like they do on the consoles.”
It's a direct replacement for Microsoft's DirectX API and people like EA's DICE and Firaxis/Stardock offshoot Oxide Games are convinced it gives them more power over today's PCs. But, somewhat bizarrely for a graphics API, it has more bearing on CPU performance than anything else. That means a low-powered CPU will be less of a bottleneck .
“Mantle - or Mantle-like technologies - are definitely necessary,” AMD's Raja Koduri explained to me. “You've seen the amount of overhead there is in current PC APIs - it's just eating up a whole bunch of CPU cycles for no good reason.”
So, in any Mantle-compatible game that's running with high CPU overheads AMD's new API should help. On titles where the GPU is holding things back, Mantle is less likely to have an impact.
Right now there is only one Mantle-compatible game around, Battlefield 4. If online shooters aren't your bag you can still start playing around with Mantle yourself with the free Star Swarm stress test from Oxide games. If you've got a GCN card you'll be able to see the performance difference straight away.
I'm ploughing through some heavier BF4 benchmark tests at the moment, but a quick look at Star Swarm on my review machine should give you an idea of the Mantle's potential. The 'extreme' test ran at 25.52 FPS on my DX11 CrossFire'd R9 280Xs with an i7 3960X and using Mantle that became 53.26. That's nearly a 110% improvement.
There's no way we'll see that sort of boost in Battlefield 4, but the Star Swarm benchmark shows what's possible when an engine has been designed to from the ground up to take advantage of the new API.
Stay tuned for Dave's BF4 Mantle benchmarks later this week.