Report of hybrid gpu system

I’ve tested today a system with one nvidia (8800gt) and one ati (4850) card and how this combination behaves in osx and win7.

win drivers – catalyst 11.4 and geforce 270.xx
osx drivers – from latest imac update.

first variant: nvidia – first card (POSTed by bios), ati – second
win7: gpu-z cant show proper info about ati card until I plug a display connector to it, then I still cant use 3d renderer of ati card, only 8800gt renderer available to opengl apps. Aida64 says only one d3d/opengl renderer available. this combo leads to a lot of instabilities of Win7. I cant run any directcompute/opencl app on 4850, system freezes.

MacOSX Snow Leopard: All works fine. Can use both renderers (8800gt and 4850) with any screen combination (for example app rendering on 4850 can be shown on screen driven by 8800gt, this leads to some fps drops, cuz system needs to copy rendered image from one card to another, but fps still at acceptable level). Can use opencl engine of any card at any time, and both in time. No problems except one – when running luxmark using both opencl devices (it cant use jsut one), the gui is very slow.

second: 4850 is first card, 8800gt is second.

Win7: even more freezes, durring running gpuz.
OSX: 8800gt wasn’t initialized by drivers, so drivers doesnt see any outputs on it, any renderers/opencl devices. 4850 works fine.


  1. MacAndor
    May 11th, 2011 | 11:53 am

    I experimented with a GTX 460 – 8800 GT combo. it looked like chameleon injected the info of the primary card, but left out the second one, so after the loading screen I got a black one… any tips?

  2. Yolanda
    May 11th, 2011 | 3:54 pm

    Try to inject your cards by ATY_init.kext, I had later config with two GTX 2XX cards and Chamellion also inject only primary card.

  3. May 11th, 2011 | 10:07 pm

    man netkas, that is interesting that you tested this.

    so far i really like osx!
    its been about 4 years running on non apple hardware.
    pretty much anything i need, i can do in OSX,

    I would have never thought you could place 2 different video cards, and
    have it not crash! this is great!

  4. Andreas / mitch germany
    May 12th, 2011 | 9:03 am

    Hi, i read that the 4850 , compared to 4870 makes much more trouble to get it working.
    What 4850 can you recommend (and is it essential to use that ATI BIOS chameleon load/use too, which bios file you use?).
    Or does newer chameleon also can inject most 4850 gpus and it doenst matter what vendor + what VGA/DVI/HDMI config they have?
    THANKS ( i plan to buy an used 4850 next weeks, reason for question).

    ///any two DVI version

  5. David Lindegren
    May 12th, 2011 | 6:15 pm

    I’ve run a ATI 4890 / Nvidia 8800 (apple version) combo since Groth/Cindori’s flash-tool was released. Works very well. One monitor on the 8800 and another on the 4890. At first I didn’t even reflect on that a similar setup wouldn’t work in windows 😉 Spoiled apple-brat indeed.

    Now I’ve replaced the 4890 with a 6870 which greatly decreased the temperature in the machine while increasing the performance. Very nice!

    Initially I removed the 8800GT altogether but since the 6870 is not bootable without some extra drivers added on SL I still have to have the 8800. Now I just hope that apple will fix this valve-engine-stuff on the 6870 and I’d be 200 % satisfied.

  6. HP
    May 12th, 2011 | 7:26 pm


    HD4850 was a big problem (for me) before 10.6.5. New releases of Snow Leopard only need you to change the Device ID in one of the included kexts.

    I can’t remember the details since I’ve sold my 4850 card but it only took a couple of minutes. No need to mess with any BIOS or difficult patches at all.

  7. Beutelkatze
    May 13th, 2011 | 6:21 pm

    I`m running 2 graphic cards aswell, no problems whatsoever.

    Mac Pro 1,1
    Sapphire 5870 rev. 2 @ uakari rom
    Geforce 7300GT – Apple stock

    Works just fine, both in Windows 7 x64 and OSX.6.7 – running dual monitors of each card.

  8. CycleBurns
    May 16th, 2011 | 3:35 pm

    Running an Sapphire 5770 and a XFX 8800gt to support 3x 30″ displays. Works perfect! Using bios replacement for both.

    Mind to put the 8800gt in a primary slot “SLOT-1”

  9. alexkord
    May 27th, 2011 | 4:29 pm

    Please help. Problem with the GPU, not work complete power off at shutdown OSX.
    Graphic card : GeForce GT 320M CUDA VRAM: DDR3-1GB.
    DSDT.aml >
    Method (_DSM, 4, NotSerialized)
    Store (Package (0x18)
    Buffer (0x0B)

    Buffer (0x08)

    Buffer (0x0F)

    Buffer (0x0B)

    Buffer (0x08)

    Buffer (0x0F)

    Buffer (0x18)
    /* 0000 */ 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00,
    /* 0008 */ 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0A,
    /* 0010 */ 0x00, 0x00, 0x00, 0x00

    Buffer (0x20)
    /* 0000 */ 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    /* 0008 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    /* 0010 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    /* 0018 */ 0x00, 0x00, 0x00, 0x00

    Buffer (0x04)
    0x00, 0x00, 0x00, 0x40

    Buffer (0x08)

    Buffer (0x17)
    “NVIDIA Geforce GT 320M”

    Buffer (0x0F)
    }, Local0)
    DTGP (Arg0, Arg1, Arg2, Arg3, RefOf (Local0))
    Return (Local0)

  10. June 1st, 2011 | 9:33 pm

    Hi guys,

    I have win 7 ult x64 installed with catalyst 11.5 and 26x.xx driver (have to check the exact version).
    I’m currently using ATI 5770 as the main renderer and GT 240 for CUDA/OpenCL stuff.
    I don’t know if netkas applied any patch to nVidia drivers (which was programmatically blocked in heterogeneous tandems), but I did it and I can use all the features offered by 5770 (opengl, opencl (tested in a brute force pass cracker), D3D and so on).

    GT 240
    Physx works in all physx-enabled games, OpenCL works (tested only in pass cracker mentioned above).
    OpenGL and Cuda thing are a little bit tricky to get working. GT240 won’t appear as an Opengl renderer by default, I should google for the solution or try to find it by-myself.
    CUDA works in most applications using the fake monitor trick.

    Извините за то, что пишу по-английски, но так я отвечу большему числу посетителей сайта.

  11. volock
    June 7th, 2011 | 7:00 pm

    I thought I’d mention my current issue here, as it may be of interest to others using mixed GPUs.

    I’ve been using the Netkas Enabler to get my current video card setup to work, and now after upgrading to Lion Developer Preview 3 it stopped working. My setup is as follows:

    Mac Pro 1,1 (Mid 2007 Model)
    PCI Slot 1: nVidia GT120 / 9500GT (Mac Version Purchased from Apple)
    PCI Slot 2: ATI Radeon 4870 HD x2 slot (Mac Version Purchased from Apple)
    PCI Slot 4: nVidia 7300 GT (Original Graphics Card, put in for testing purposes)

    The ATI card and the nVidia 7300 work without anything extra being installed or done. Because my Mac has a 32 bit EFI instead of a 64 bit EFI, the nVidia GT120 won’t work without the enabler. I have had this setup working in all version of Leopard 10.5.x and Snow Leopard 10.6.x but am unable to get any display detected after installing Lion DP3. The card is properly detected. My other two cards are working fine under lion and have no issues.

    Just a side note about my card’s ordering… The system is happiest with the GT120 in slot 1, if it’s in any slot. Any other slot and I see huge FPS drop (with/without enabler installed and on all OS versions). The extremely funny part about this is that if I have the setup as it is now, or with the ATI card in slot 1 and GT120 removed completely, I get the same benchmark numbers on the ATI and the 7300GT, but if I have all three cards in, in any other configuration that posted above, I see huge drops (independent of which OS).

    If anyone has any ideas on how I can get a display working on the GT120 again please help. Thank you.

  12. June 11th, 2011 | 5:36 pm

    @volock Throw that GT120 away, it’s too weak/old. Put 4870 x2 into the PCI-E slot 1 and 7300 into the second slot.

  13. John Volock
    June 29th, 2011 | 12:01 am


    I know it’s old and dated but I don’t have money for a new nVidia card and I’m mainly using it for CUDA projects.

  14. xfx4850
    August 7th, 2011 | 2:32 am

    Hi Netkas.
    You say that 4850 is working in 10.7 and it is but : 2 dvi card, dual screen problem, 1st screen if fine, but second [screen 2] is recognized as VGA, and is black screen, or in best case just VGA resolution.
    On 10.6 is working just fine.

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