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GPU and OpenCL

theSeb

theSeb

macrumors 604
Original poster
Aug 10, 2010
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I realise this is not the specific forum for this discussion, but I find that the most knowledgeable people hang around these parts so it's worth a shot. There are many threads on these forums where people ask, "What computer should I get to do xxxx". The nearly automatic responses are usually along the lines of, "Don't get so and so if you're working with graphics because it has integrated graphics / rubbish graphics card".

The question for me, however, is just which applications actually utilise the GPU to perform processing? As far as I know the only way to do this in Mac OS is via OpenCL so I assume that my real question is which applications actually use OpenCL. I believe that Final Cut X uses it, but I am curious if this is correct and if there are others? Does any one know of a definite list?
 
theSeb said:
I realise this is not the specific forum for this discussion, but I find that the most knowledgeable people hang around these parts so it's worth a shot. There are many threads on these forums where people ask, "What computer should I get to do xxxx". The nearly automatic responses are usually along the lines of, "Don't get so and so if you're working with graphics because it has integrated graphics / rubbish graphics card".

The question for me, however, is just which applications actually utilise the GPU to perform processing? As far as I know the only way to do this in Mac OS is via OpenCL so I assume that my real question is which applications actually use OpenCL. I believe that Final Cut X uses it, but I am curious if this is correct and if there are others? Does any one know of a definite list?
Click to expand...

I had not heard of any professional applications using OpenCL. Was surprised to read that Final Cut X does.

As someone who has worked with OpenCL there is a very good reason why we don't see this -- no support on Intel GPUs, no OpenCL Image support on many GPUs that do support OpenCL, and very bad drivers that will kernel panic your machine at the slightest error in a lot of cases. My Geforce 8800 GT actually (literally) blew up when I was running an OpenCL program I'd written.

There are other ways to do GPU computation on Mac OS X besides OpenCL. You can use Core Image, or GPGPU using OpenGL shaders (this is the old school way to do it). Macs with NVidia GPUs also support CUDA (which is very similar to OpenCL).
 
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the primary purpose of discrete graphics cards is for 3D graphics. 2D has no large demands, and things like H.264 hardware acceleration aren't exactly demanding, either. OpenCL/CUDA/GPGPU support is pretty rare and isn't really a consideration.

if you don't do 3D, there's no reason to spend more on a better GPU.
 
holmesf said:
I had not heard of any professional applications using OpenCL. Was surprised to read that Final Cut X does.

As someone who has worked with OpenCL there is a very good reason why we don't see this -- no support on Intel GPUs, no OpenCL Image support on many GPUs that do support OpenCL, and very bad drivers that will kernel panic your machine at the slightest error in a lot of cases. My Geforce 8800 GT actually (literally) blew up when I was running an OpenCL program I'd written.

There are other ways to do GPU computation on Mac OS X besides OpenCL. You can use Core Image, or GPGPU using OpenGL shaders (this is the old school way to do it). Macs with NVidia GPUs also support CUDA (which is very similar to OpenCL).
Click to expand...
Thanks for the info. I wasn't aware that CUDA is supported in Mac OSX.

So there are alternatives for GPU computation, besides OpenCL, but do you know which mainstream applications use any of these?
 
ATI is putting their eggs in the OpenCL basket. Nvidia is CUDA. Proprietary problems for consumers on the horizon. OpenCL is not very prevalent. CUDA is but there are no current consumer Nvidia GPU's you can buy. A used GTX285 is the best consumer grade or bite the bullet and get a more expensive and still slower Quadra. Once again greed and market control to blame.
 
Final Cut Pro X and Motion are about the only ones right now. I know of a lot of work being done on OpenCL apps, so that will change in the future. There's a good chance the next version of Premiere Pro will support OpenCL.
 
Hey Toxic,
Is this really true across the board? Only 3D apps gain a benefit from a better video card with better open GL? I have a mac pro 1.1 with a 7300gt card in it doing primarily after effects work. The 7300 is a total crap card and I will be extraordinarily disappointed if I don't see a decent improvement once I pop my 6870 in there. I don't play games, just do work with this machine.

Thanks for the info,
 
Bhang said:
Hey Toxic,
Is this really true across the board? Only 3D apps gain a benefit from a better video card with better open GL? I have a mac pro 1.1 with a 7300gt card in it doing primarily after effects work. The 7300 is a total crap card and I will be extraordinarily disappointed if I don't see a decent improvement once I pop my 6870 in there. I don't play games, just do work with this machine.

Thanks for the info,
Click to expand...

Which version of after effects are you using?

I've found some interesting info over here for CS4: http://kb2.adobe.com/cps/405/kb405445.html

After Effects CS5.5 - http://www.adobe.com/products/aftereffects/extend.html

Photoshop CS5

Photoshop is taking
advantage of the powerful processor contained on these cards (called
the graphics processing unit or GPU) to help speed up performance
and activate a set of special GPU-accelerated features such as canvas
rotation, panning and zooming, Adobe Repoussé, and Adobe Pixel
Bender® filters (available for download from labs.adobe.com).
Photoshop CS5 uses the GPU when the installed video card supports
the OpenGL standard and has a least 256MB of VRAM (512MB or more
is better for 3D work)
Click to expand...

Well that basically answers my questions.
 
I'm not that familiar with AE, so I can't really say how much or how well it utilizes GPU power. PS CS5 doesn't use much of any GPU power, despite what they might make you think. benchmarks make me think CPU cores and clock speed still rule for FCX and AE.
 
CUDA and Mercury playback are a game changer for Premier. When it was demoed the video people had their jaws on the floor. Then Adobe said that there are no GPU's currently supported for Mac except Fire and Quadro cards. Any Nvidia GPU with CUDA will work but there are currently zero for Mac Pro's since EVGA put out the GTX 285 which is still faster than the 1000.00 Quadro.
 
toxic said:
benchmarks make me think CPU cores and clock speed still rule for FCX and AE.
Click to expand...

It depends. GPUs have helped a lot for real time previews, but for actual rendering, CPU speed is still king.
 
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