Some More Information on AMD’s Mantle
During the AMD's GPU product showcase last month the new Mantle API was news we had not expected. Unfortunately, AMD provided little detail during the event and we will have to wait before games using it will appear. However, French site hardware.fr managed to get some more details from AMD's Raja Koduri (Interview transcript is in English).
Koduri says that Mantle has been in development for 5 years and was the result of game developers asking for more direct access to PC hardware. The timing of Mantle's announcement was due to the shifting focus of developers:
"The idea started then but the timing in terms of when it was the right time for us to do happens to be now. With the new console generation and architecture compatibility it just came together right at the perfect moment for us.
I wouldn't say that because this is driven more by the game developers than us, so the game developers are ready for major kind of tests, working on new engines, new stuff and they really want to take the PC as a first class citizen. They don't want to forget it as they're architecting their engines for new consoles. They really want to make sure that PC performance moves forward. It's a better timing from a game engine stand point than AMD stand point.
If the game engines [developers] were ready to say "hey we'll put dedicated effort", if Johan came to us and say "I have time I will do the work now" and half dozen other people like Johan also put their hands up, I'm sure other companies and AMD would have say yes years ago to do that thing but they were busy with the last generation consoles, PC and other stuff. Now they're ready."
Technical details are still quite blurry however. Koduri was told that Mantle specification is very broad and constantly evolving. New versions may ship both in games themselves and in the Radeon drivers. It also is not a replacement for standard DirectX and OpenGL APIs, but an additional option for developers who want to use it. AMD's teams working on standard APIs are still 20 times larger than the Mantle team. Koduri does not consider the introduction of Mantle as the risk of fragmentation, as it will be included in the big middleware game engines, which will take care of all the different ways to access hardware.
While the claim of Mantle being an open standard and an industry standard was repeated several times during the interview, the details were too blurry. The way other hardware companies may utilise it and how well non-GCN hardware will work with it remains a mystery, as it was mentioned only in very uncertain terms. Same uncertainty applies to it running on future AMD GPUs based on a different architecture.
While AMD's representative was quite cryptic about Mantle and its capabilities, John Carmack has shared what he thinks about Mantle and its performance claims on Twitter. He considers the famous claim of 9x more draw calls over the Direct3D legit, but says that Nvidia's OpenGL extensions can get that result as well. He also thinks that Mantle could give a big boost to Steam Machines, leading to bad relations between AMD and MS/Sony. Carmack himself is not planning to work with Mantle, as his choice is OpenGL working on different hardware, 3 major PC OS lines and mobile platforms.
Even with all this news there is still a lot to learn about Mantle. AMD are likely not giving completely unrealistic promises, but to learn more we will have to wait both for the developers conferences and the first games with Mantle support this year. Depending on the developer support, reduced CPU load and improved graphics multithreading from Mantle is extremely important for AMD CPUs, which only compete well against Intel in highly threaded workloads. On the brighter side for non-GCN cards, we may see more performance improvement work on DirectX and OpenGL if Mantle becomes a successful competitor.