OpenCL and SnowLeopard

Now about openCL technology in snowleopard:

there is two types of opencl devices available to system in SL, it’s CPU and GPU

CPU is most feature rich device and exist on all macs/hacks with SL installed.

[Device 1]
Name: Intel(R) Core(TM)2 Quad CPU Q9450 @ 2.66GHz
Vendor: Intel
Type: CPU
Device Version: OpenCL 1.0
Driver Version: 1.0
Compute Units: 4
Work Group Size: 1
Clock: 3072 MHz
Global Memory (Total): 6400 MB
Global Memory (Host): 6144 MB
Global Memory (PCIe): 256 MB
Local Memory: 16 KB
Cache Size: 6144 KB
Cache Line Size: 64 Bytes
Available: Yes
Double-Precision: Yes

Second Possible OpenCL device is GPU, opencl supported on almost all nvidia gpus with unified shaders architecture, so its all geforce8+

Radeon side is poor, only radeon hd 48×0 cards support OpenCL in SL.

Name: Radeon HD 4870
Vendor: AMD
Type: GPU
Device Version: OpenCL 1.0
Driver Version: 1.0
Compute Units: 4
Work Group Size: 1024
Clock: 750 MHz
Global Memory: 128 MB
Local Memory: 16 KB
Cache Size: 0 KB
Cache Line Size: 128 Bytes
Available: Yes
Double-Precision: No

All info you see here(clocks, memory, etc) is hardcoded in ATIRadeonX2000GLDriver.bundle.

There is 3 device types hardcoded in file – radeon hd 4870 (used also for 4830 and 4850),
mobility radeon hd 4850 (used in imacs), and RV790 (hd 4890).

Radeond OpenCL support is very poor, only few of many apple’s opencl demo run on it, this opencl banchmark will result in errors in graphics driver and graphics will stop working untill reboot. the error was due to benchmark used too much local memory(driver should handle that and not just stop gpu), and results is that 4870 is 1.5Β  times faster than c2q 3ghz, but 15 times slower than gtx285

No OpenCL support in intel graphics.

Good luck with openCL.


  1. local
    August 26th, 2009 | 12:43 pm

    Interesting, is there any way of checking if it is enabled for the GPU?

    Have an 8800GTS and 8400 and I’m looked for a OpenCL GPU Enabled somewhere πŸ™‚

    ///oclinfo –

  2. shadowmajk
    August 26th, 2009 | 3:11 pm

    Nice CPU 17sec/ GPU 2.7 πŸ˜€ not so bad πŸ˜‰

  3. local
    August 26th, 2009 | 3:37 pm

    Oh, thanks, 2 OpenCL devices found, very nice πŸ™‚

  4. graebags
    August 26th, 2009 | 5:22 pm

    Q9450 17.11 / GF8800gts 2.46, valid=yes

  5. Paul
    August 26th, 2009 | 5:59 pm

    Thanks for clarification. πŸ˜‰

  6. Andreas / mitch germany
    August 26th, 2009 | 7:20 pm

    Hi, i am, mitch/germany, made and shared that small OpenCL Bench tool.

    Better to download it from “home” site – always newest versions also an result collection & error report .

    Newest Version is V020 (shown at runtime in first lines).
    V020 has much error handling added for ATI problem of OS X freezes.

  7. cmf
    August 26th, 2009 | 8:08 pm

    thx for the info … just made me find a dumb bug in oclinfo :>
    so cl_APPLE_gl_sharing should be supported at least.

    sad that apple didn’t find it necessary to support all extensions that the hardware is capable of … in their final release :/
    on the other hand, maybe apple just gets the source code from amd/ati and since they don’t support opencl in their drivers either that could be the reason.

  8. yyll
    August 27th, 2009 | 4:18 am

    My ATI HD 3850 can’t open QE/CI in snow leopard,the ATIRadeonX2000GLDriver.bundle(SL) doesn’t work.
    And i put the ATIRadeonX2000GLDriver.bundle in leopard to SL,but it doesn’t work either.
    It’s really no idea to this!?

  9. Andy
    August 27th, 2009 | 6:40 am

    Your ATI HD 3850 couldnΒ΄t work as an OpenCL device because its GPU is not supported…

    For the moment there are just ati 48xx cards supported from apples side

    and naturally a few more nVidia cards πŸ™‚

  10. ricola
    August 27th, 2009 | 2:45 pm

    9400 GT : 3.992 seconds
    E7500 : 12.048 seconds

    Validate test passed

  11. oscarbg
    August 27th, 2009 | 7:27 pm

    Hi, netkas what are you refering to:
    only few of many apple’s opencl demo run on it

    Where are it?
    In new Xcode, or in the web

    Please share it..

  12. np_
    August 28th, 2009 | 9:20 am

    netkas, seems you are ATI lover,
    that for i wonder why you don’t lose your time in some interesting like to make proper ATI drivers for osx – AMD guy’s are not “dick heads” like nvidia and they do provide any resources , sources , info enough to build nice driver for ATI .

    //// why you don’t lose your time
    /// thats why.

  13. mappy
    August 28th, 2009 | 1:22 pm

    I’m wondering what Video card to use with Leopard to get the best results, so this is my understanding of where we stand now.
    – the 285 GTX is fast and fully supported by Apple and by Leopard/Snow Leopard
    – it’s expensive, too expensive
    – support in SL is limited to a few cards
    – 4870 and 4890 cards made for PC can be adapted to a Mac or a hackintosh
    – 4890 is the most powerfull, 4870 can be found at a really good price and is a little less powerfull
    – avoid the 2GB version because they have issues
    – everything works in SL including connecting 2 screens to the same card

    Am I correct?
    Than what is the best version of the 4890 to buy? Is a Sapphire 4890 !GB a good option?

    ////dont go 48×0 if you are planning to use dvi2vga

  14. foo
    August 28th, 2009 | 7:34 pm

    Does anybody know if the 3870 will be supported in 10.6.1 in QE/CI Mode? I don’t see why OpenCL is limited to 4xxx Radeons, but QE/CI support for the HD 3xxx series would definitely be a great thing to start with!

  15. macmunch
    August 29th, 2009 | 4:34 pm

    hi friends

    I want to build 2 Hackintoshs with P5Q Pro Mainboard

    But Right now I have a problem with the choice of the Graphic card !!

    which low cost card can I take ?? Geforce 9600 ?! Radeon 4830 which one doesnt make any problems and you can play some games … ?

    But the Card MUST support 2 Displays ?! So OS X must be able to give 2 singals out there ?!


  16. netkas
    August 29th, 2009 | 8:00 pm

    two opencl demos for nvidia cards –

    Galaxies demo without gpu support (works on radeons)

    Galaxies (present ion both archieves) is good benchmark, click on SIm button to select fastest device

  17. August 30th, 2009 | 5:54 pm

    Thanks for the interesting post netkas!

    Hopefully ATI will step up to the plate for OpenCL performance.

  18. Arie Boutendraaier
    August 31st, 2009 | 10:12 am

    Is there any overview available with videocards which are both supported by OpenCL and EFI-strings ?

  19. Andreas / mitch germany
    August 31st, 2009 | 1:17 pm

    I got an report that Galaxy (Apple Source, compiled by me) on an IMac with ATI 4850 also didnt run – bus error.
    Seems that OpenCL part of ATI, which does an “compile on the fly” for the gpu has problems.
    Got MacPro Early 2008 result: GPU 95 Gigaflops, but 8800NV “only” 60 Gigaflops.
    Means: The faster the cpu the more is an really new+fast gpu needed. Without at least an NV GTX260 an new i7 / MacPro 2009 didnt make much sense.
    But an 8800GT outperforms any C2D <= 3 GHz.

  20. Andreas / mitch germany
    August 31st, 2009 | 1:20 pm

    EDIT: ” CPU(not GPU) 95 Gigaflops, but GPU 8800NV β€œonly” 60 Gigaflops.”

  21. Spacedust
    August 31st, 2009 | 5:57 pm

    ……………… OpenCL Bench V 0.25 by mitch ………..
    …… C2D 3GHz = 12 sec vs Nvidia 9600GT = 0,93 sec ……
    … time results are not comparable to older version! …..

    Number of OpenCL devices found: 2
    OpenCL Device # 0 = Radeon HD 4870
    Device 0 is an: GPU with max. 750 MHz and 4 units/cores
    Now computing – please be patient….
    time used: 6.270 seconds

    OpenCL Device # 1 = Intel(R) Xeon(R) CPU E5345 @ 2.33GHz
    Device 1 is an: CPU with max. 2330 MHz and 8 units/cores
    Now computing – please be patient….
    time used: 3.842 seconds

    Now checking if results are valid – please be patient….
    πŸ™‚ Validate test passed – GPU results=CPU results πŸ™‚

  22. damned42
    August 31st, 2009 | 10:17 pm

    I have tested both cards (4890 and 285 gtx mac edition): I have to say that Open CL benchmarks are not very useful. why ? Apple Pro apps are not using it for instance…
    In all tests I’ve run Under Motion, 4890 is average 40 % faster than the GTX.

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