Meh, you have a long way to go to convince me that both A) these techniques are significantly and noticeably better and B) that they can't be made to work just fine on CPUs. The slides even quoted 20% of what I imagine is a single CPU core for a convolution reverb (which is arguably not even the best bang for the buck algorithm to use, but alas)... that's completely within the realm of reasonable. Modern CPUs can handle *tons* of channels and effects if half decently optimized... just check out some modern DAWs if you don't believe me. So yeah, extremely not convinced and sad that I wasted an hour watching that part of the presentation.This isn't an "audiophile" thing, its an audio immersion thing. Techniques are available to bring more realistic sound within (gaming) environments, but they generally suck up CPU horsepower, to the point where game devs don't do it because it pushes the bar too high.
The Mantle mention is definitely more interesting, but I think we really need more information before getting excited. In particular, how does it interact with WDDM? Do things remain as robust and orthogonal as they would in a standard DX context? i.e. does it interact properly with the compositor (can I run it in a window?), memory subsystem, TDR, pre-emption, etc? I imagine the solution here must involve stuff like carving out big regions of memory that you just claim are in-use to WDDM, but that can actively interfere with the OS's ability to allocate resources in multi-context situations. I'm guessing the assumption is that this is primarily going to be for "full screen gaming", but if those limitations go too deep, I'm going to be much less interested. Robustness/stability is also a concern, but only time will tell on that one
The SteamOS angle is interesting, but has political problems in the Frostbite case due to EAs (poor) treatment of the Steam relationship in the past. Hopefully either other games can make use of it or EA relents on their need to control everything.
To those of you who think this is going to be just a different API that other vendors can support, I think that's extremely unlikely. They made that fact that it was "very low level" and specific to GCN quite clear. The point is one version of Mantle may only support one or two generations of AMD GPUs, and even forward compatibility is not entirely certain. Yeah, it's entirely possible that when you upgrade to your R3xx or R4xx GPU BF4 will get slower due to having to fall back on the DX11 path. Perhaps they are going to try and maintain better forward compatibility, but that's far from given... compatibility and low-level performance are often at odds and anything they do there sacrifices some of the efficiency they are trying to gain. (Or worse, it handcuffs future hardware architecture.)
Uhh, I'm not sure that's entirely fair. In particular, GPU memory is still owned by WDDM. If you accept that, I'm not convinced you can do a lot better than GL/DX do today. If you don't and start playing games with lying to WDDM and using huge chunks of memory - which I imagine is what Mantle does in practice - then more things are possible, but there's also potential OS issues.OpenGL is fully out of the domain of Windows and wholly in the hands of the IHV's, Mantle will be no different in this respect. Memory re-write was already implemented many releases ago.
I think the point people dance around a bit too much is that properly supporting multi-application, multi-context situations with foreground/background applications over a wide range of harder is a legitimately harder problem than what consoles have. Thus while I'm the first to say there are inefficiencies still in the software stack (see my interview which was linked earlier), let's not pretend there's a free lunch to be had here with zero compromises. It's really just more of a question of where Mantle lies in the space of abstraction/compatibility/OS features vs. low-level/performance.
I also thought it was interesting to note that Eyefinity and Crossfire were listed explicitly as part of the DX11 release of BF4, not the Mantle update. Perhaps I'm reading too much into it, but I wouldn't be surprised if something like Mantle makes the games that these features play in the driver more difficult/impossible to do and thus games themselves would have to explicitly support them. That wouldn't really be a bad thing IMHO as I've made my feelings on multi-GPU abundantly clear on these forums, but yet another consideration.
Anyways, fun times ahead - looking forward to more concrete info! Cautiously optimistic.
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