Considering the boost Mantle could give to a steambox, MS and Sony may wind up being downright hostile to it.— John Carmack (@ID_AA_Carmack) September 26, 2013
AMD's Mantle is a low-level API for its "Graphics Core Next" architecture that promises to bring unprecedented graphics performance to the PC.
One of the advantages consoles hold over PCs is that as standardized pieces of hardware with a long lifespan, developers can program "close to the metal" and squeeze more performance out of them. PCs, on the other hand, are generally restricted to high-level APIs like DirectX, which allows software to run across a variety of components and configurations at the cost of a fairly substantial performance hit. Muscular video cards compensate for API inefficiencies but their full power goes untapped; with Mantle, however, AMD intends to combine GPU drivers with a low-level API that will allow programmers much more direct access to the display hardware, and thus to unlock much more of their potential.
It may not seem like the most exciting topic ever but it's actually a very big thing. Mantle supports new rendering techniques and offers direct access to all GPU features, and promises to simplify game development by "leveraging commonalities" between Graphics Core Next-equipped PCs and consoles. But the big issue is performance: High-end GPUs can process far more draw calls than high-end CPUs can typically submit, according to Anantech, but AMD claims Mantle enables nine times more draw calls per second than current APIs, potentially revolutionizing the rendering capabilities of PCs. PC versions of multiplatform games will also be able to take advantage of many of the performance-boosting optimizations currently exclusive to consoles.
Id Software mastermind John Carmack noted on Twitter that Mantle could do big things for Valve's Steam Machines as well, although that may bring headaches from Sony and Microsoft. "AMD has an interesting opportunity with Mantle because of their dual console wins, but I doubt Sony and MS will be very helpful," he said, referencing the fact that both the Xbox One and PlayStation 4 make use of AMD's GCN architecture. "Considering the boost Mantle could give to a steambox, MS and Sony may wind up being downright hostile to it."
And as great as it promises to be, it faces the same challenge as any low-level API in the PC arena: different hardware manufacturers with different architectures. Old-timers will remember Glide, a proprietary low-level API from 3dfx that allowed for unprecedented visual fidelty - as long as you had a 3dfx card. But it was eventually muscled out by Direct3D and OpenGL, which traded performance for compatibility and allowed for "one size fits all" game development. Mantle will face the same challenges, although AMD claims that this is actually something developers have been asking for for years; DICE actually put together a presentation for the Mantle unveiling, announcing that its Frostbite 3 engine will render with Mantle instead of DirectX 11 on compatible GPUs. The upcoming Battlefield 4 will be the first game to launch with Mantle support.
A far more detailed breakdown of Mantle is available at Anandtech and it's a worthwhile read for anyone interested in the nuts and bolts of this stuff, but the bottom line is that AMD could have something truly game-changing on its hands, and if it takes, some very big things could happen in the world of PC gaming in the not-too-distant future. AMD said it will reveal more about Mantle at the AMD Developer Summit in November.