DirectX 11 & future of CPU

[Firestrider]

I've asked similar questions in the past, but never got a clear cut answer.

When DirectX 11 comes out and becomes mainstream, what will happen to the CPU in games?

The compute shader could be used for physics, AI, audio, network, and simulations on the GPU that are typically done on the CPU.

Of what importance would the CPU be by then?

[Kampfzerstorer]

It'll run the Operating System that in turn makes it possible to play your game in the first place.

[freakdiablo]

I think it'll still be used for those things and they will be balanced for best performance between the cpu and gpu. After all, the main purpose of a graphics card will still be rendering pretty pictures.

[e6600]

probably left to dx10/9/8 games which many people still do play

[BackBreaker]

so does that mean youll need a super graphic card a lot more powerful than todays 9800 gt's for example to play any game due to everything being done on the gpu? Does that also mean you can for instance buy a super expensive graphic card and I could keep my x2 2400+ without replacing the mobo and cpu forever?

[Kampfzerstorer]

so does that mean youll need a super graphic card a lot more powerful than todays 9800 gt's for example to play any game due to everything being done on the gpu? Does that also mean you can for instance buy a super expensive graphic card and I could keep my x2 2400+ without replacing the mobo and cpu forever?

They'll probably find some other thing to waste CPU cycles on.

But I agree with your first question, if you start using the GPU for other random tasks it'll have less available resources to do its "main" job.

[shard]

I would like to see the OS get cached to the RAM (16+gb ftw) and the CPU gets put to full duty calculating everything but renders. Alot of power that can be utilized that ends up being wasted on junk.

[jmdixon85]

Thats a very good question my friend. For instance, I've been playing the new tomb raider game and I have a sidebar app in Windows Vista that records the CPU usage. While playing the game Ive noticed that my CPU usage is around 75%. And my CPU is only a E4600 @ 3.3Ghz. And this is with the GFX maxed out and only running on one 8800GT. With physX now being run on the GPU in most new games and some great hardware soundcards (Thanks ASUS, booo Creative!), The CPU will be left ticking over doing simple network and I/O tasks.

[mastrdrver]

Will current DX10 GPUs being DX11 compatible?

[deathman20]

so does that mean youll need a super graphic card a lot more powerful than todays 9800 gt's for example to play any game due to everything being done on the gpu? Does that also mean you can for instance buy a super expensive graphic card and I could keep my x2 2400+ without replacing the mobo and cpu forever?

Ha hope your joking ;) Todays GPU's need powerful CPU's to perform to there fullest, and CPU's need to be powerful to handle the games these days. Its not a one or another its both. You need CPU power for the game itself, but also the OS, Background Apps, and Proccesing information for the GPU itself.

[metloaf]

Well said. ^ This is why we see bottle necks in certain setups. Most GPUs need pretty fast CPUs to keep them "fed" with more cycles to process. As far as Dx10 goes it is rumored to be backwards compatible with Dx 10 however it will be hardwired into the new gfx cards and the new OS coming out. :beer:

[Firestrider]

Ha hope your joking ;) Todays GPU's need powerful CPU's to perform to there fullest, and CPU's need to be powerful to handle the games these days. Its not a one or another its both. You need CPU power for the game itself, but also the OS, Background Apps, and Proccesing information for the GPU itself.

I think he is thinking with the future of GPU. Most of the stuff that is currently done on your CPU in games which in turn bottlenecks your system can be done on the GPU in the future (with DX11 and OpenCL). What other things besides the GPU driver HAVE to be done on the CPU when playing just a game (all other processes can be put to sleep)?

They way I understand it is the GPU is just a big execution engine for massively parallel workloads, and the CPU basically fetches and decodes instructions to send to the GPU to execute. In that case isn't the CPU's execution units inferior? Wouldn't it be more efficient to have have GPU "cores" on the CPU die?

[deathman20]

I think he is thinking with the future of GPU. Most of the stuff that is currently done on your CPU in games which in turn bottlenecks your system can be done on the GPU in the future (with DX11 and OpenCL). What other things besides the GPU driver HAVE to be done on the CPU when playing just a game (all other processes can be put to sleep)?

Well even future GPU's are the same way. There will not be 1 standard for every game out there say. So even if 1 game can utilize the GPU better than others for say Physics processing doesn't mean the next game will use the GPU for Physics procesing on the GPU, it could all be done on the CPU.

And even playing games there is still other processes that will not sleep and take up CPU cycles, no matter what you do there is always overhead, mind you on a fast CPU its basically nothing, but on a slower one it could be noticable. Like my case Vista with my setup it idles at around 1-3% CPU cycles, but if its a slower CPU then that will climb and have noticable impact on gaming performance if its a high CPU usage game.

[Drew@PSU]

I don't think that a super GPU is really going to render the CPU obsolete in any sense of the word. The CPU and GPU need to work as a team ( "in parallel" would be a poor choice of words there methinks ) to make the best gaming experience. If you code your game to just use the GPU through the DX11 API, you are neglecting lots of available computing power. While you could do all of these things ( network, AI, physics, etc ) on the GPU, the CPU isn't going away, you might as well use it. I take it this question stems from the efficiency of highly repetitive tasks on GPUs? ( Or parallel tasks I suppose is more correct )

[deathman20]

Well only issue as well loading everything onto the GPU, the GPU still has to do graphics rendering. If its taking all the Physics and AI onto the GPU, the CPU still has headroom, expecially if its a multi-threaded program, which its wasting power on by slowing down the video at the expense of the GPU speed.

[Firestrider]

Thing is with the DX11 API you can load balance between the GPU and CPU with the compute shader, but the GPU is a lot more power performance efficient in parallel computational workloads so it would make sense to use it for anything you can. I think the RV770 core has a 110W TDP for 1-1.2 TFLOPS while Core i7 has a 125W TDP for 51 GFLOPS

[deathman20]

Yeah if the GPU is programed for it, and the game is programed to use the GPU for it. Which means that a common language would have to be used between ATI and nVidia GPU's which for programing wise doubt that will happen anytime soon.

[Mr.Guvernment]

id idnt read it all, but %99 of programs use a CPU to run, not a GPU, so as others said, the cpu will do everything else it has always done since the beginning of time, run your computer and everything else on it.