HD3870 and OpenCL

Discussion in 'Mac Pro' started by artinnj, Sep 6, 2009.

  1. artinnj macrumors newbie

    May 23, 2009
    Looks like Snow Leopard uses drivers that are not OpenCL enabled when you have a HD3870 in your MacPro.

    As anyone been able to change their driver settings to enable this feature?
  2. 2002cbr600f4i macrumors 6502

    Jun 21, 2008
    3870 isn't supported. Sorry!

    To be honest, I have the 4870 and the couple OpenCL things that I've tried that I have been able to get working haven't really impressed me with their performance.... In fact, my 2.93 ghz 2009 Mac Pro Quad's processor actually runs OpenCL code faster than the 4870 does! I'd imagine the 3870 would be even worse.

    ATI's drivers just aren't up to the task (YET).
  3. ungraphic macrumors 6502a


    Nov 15, 2007
    Toronto, Canada
    Just to clarify for those who aren't informed:

    The ATI HD3870 has the hardware which is more than capable of running OpenCL. However, either ATI or Apple are responsible for writing the drivers to give proper support for our card.

    I think OpenCL has been poorly implemented, or poorly developed. I haven't seen a single review or opinion of any single legit news source or a random opinion from anyone, be it blogs, forums or friends, saying anything other than (basically) 'OpenCL doesnt seem to change much'

    I was really expecting OpenCL to take a load off the CPUs in my Mac Pro, but such is not the case. There was far too much hype from steve jobs and his reality distortion field about how great OpenCL would be, when, as you guys can clearly see, hasnt done much.

    Snow Leopard seems like its mostly small insignificant tweaks, no major performance gain other than a few long overdue features; airport in menu bar finally showing signal strength and security for connections, the finder getting a slider for icon sizes and a good slimming down of the overall space used up by OS X.

    Anyway, back to the point:

    Apple *better* get OpenCL properly implemented and *better* give us support for our HD3870s.
  4. elbows macrumors regular

    Oct 27, 2005
    People who are expecting OpenCL to change the performance of their day-to-day computing at this stage, are barking up the wrong tree. Certain computational tasks are going to benefit from such technologies, but only when developers add support.

    Right now, apart from running OpenCL benchmarks, pretty much the one area where a user is going to notice OpenCL support is if they use Quartz Composer with any of its OpenCL patches. Using examples provided, I can make particle systems, 2D Fluid Simulations and 3D mesh deformers that use OpenCL. But OpenCL CPU support in Quartz Composer is currently broken, so these things wotn run at all on my Mac Pro with ATI3870. I shall get a GTX285 at the earliest opportunity.
  5. 2002cbr600f4i macrumors 6502

    Jun 21, 2008
    Exactly... In general people seem to be under the misguided illusion that just by installing Snow Leopard everything was going to run so much faster that it did under Leopard immediately.

    That is FAR from reality!!!!

    If you read the Snow Leopard review on Ars Technica, he goes into really good detail on exactly what changed in SL, and why that's going to ALLOW eveyrthing to run faster ONCE DEVELOPERS MAKE USE OF IT!

    Right now, it's Quartz and CoreImage that are the only parts of the OS using OpenCL.

    Even the Radeon 4870 driver for OPenCL is borked. Only about 1/3 of the developer demos will even run on my 2009 Pro w/4870. Somebody in the OSX forum posted a Quartz Composer based OpenCL visualizer for iTunes. When I run it, it pegs my CPU to 500% because the OpenCL code is going to the CPU instead of the 4870 (assumingly because the 4870's driver doesn't support something that's required...)

    Briefly - SL did 4 things:

    1) they changed the compiler to LLVM
    2) they added Blocks to Objective-C and C and C++
    3) They added Grand Central which, when used with 1+2 allow developers to stupid-easily make their code multi-threaded, and when they do so, it'll use as much computational hardware as your machine has available.
    4) OpenCL, when used properly can offload CERTAIN data-parallel processing tasks to SUPPORTED GPUs.

    Given that OpenCL is very similar to NVidia's CUDA platform, its no surprised that right now, the NVidia cards can do OpenCL a LOT better than the ATI/AMD cards. Hopefully that will change over the next 6 months as Apple+ATI get things figured out.

    Regardless, OpenCL won't do squat until developers write their code to use it.

    Snow Leopard didn't make things faster. It provided the infrastructure and developer tools to ALLOW things to take full advantage of multiple cores and GPU's easier. But until developers change their programs to make use of these tools, things aren't going to really be any better.

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