1 GTX 680 and (1 HD 5870 or 1 HD 5770) in Mac Pro?

Discussion in 'Mac Pro' started by silvercircle, Aug 13, 2012.

  1. silvercircle macrumors member

    Nov 18, 2010
    Now that I have my GTX 680 installed in my Mac Pro 5,1, I have a HD 5870 which isn't used.
    Provided that I use an external power supply for both cards, is it possible to install both these cards? That way I would have a boot screen again to boot older system versions etc.

    I don't think there is enough space between them to let cooling air in.
    Anyone tried this? Maybe a HD 5770 is a bit smaller? I know you can get a Mac Pro with two HD 5770 installed, so....?
  2. jav6454 macrumors P6


    Nov 14, 2007
    1 Geostationary Tower Plaza
    An HD5770 is the same size (in terms of vertical space) as a GTX690 and HD5870. The difference is that the HD5770 is smaller length-wise.

    Yes you can have both the HD5870 and GTX 680 in there with an external power source. However, I am not sure they will play nice.
  3. silvercircle thread starter macrumors member

    Nov 18, 2010
    Works but fps drop

    I did the test, borrowed a HD 5770 and installed it next to the GTX 680.
    It works but, like you said, frame rate drops significant.
    On the GTX 680 Unigene Heaven benchmark goes from 1979 down to 1212, fps from 48 down to 78 (gtx 680). GTX is set a main screen of course.

    Well, I can run Lion on Parallels now. So I only need my GTX 680.
    If I ever need a boot screen again I can always plug the HD 5870 back in.
  4. BigJohno macrumors 65816

    Jan 1, 2007
    San Francisco
    This was actually what I was going to do when I got my 670. I have a 5770 currently. Why would it be affecting the frame rate when os x renders each monitor independently of gpu? Would you see a performance hit in photoshop or illustrator?
  5. silvercircle thread starter macrumors member

    Nov 18, 2010
    I don't know why this happens but it does. I tested it.
    I can not tell you if the same goes for photoshop or illustrator, I don't have those app's.

    Another annoying thing is that when you connect the 5770 to an external power supply, the fan spins as long as the power supply is on. So, when you put your MP to sleep the fan keeps on spinning.
    I guess you can connect this one to the internal power connector and connect the GTX to an external supply. The fan of the GTX doesn't start spinning.

    It was always a problem when 2 brands of GPU are installed. When I rebooted in Windows, the GTX wasn't working anymore.
    My guess is that if you wan't a boot screen and your GTX, install a GT 120 (or whatever card was used in the first Intel Mac Pro's).
    I found an old Geforce 8800 and there was no loss in performance when I installed it next to the GTX.
    I don't remember from which computer this card was, but since there isn't a boot screen, it must have been a G5. I never owned another computer.
  6. BigJohno macrumors 65816

    Jan 1, 2007
    San Francisco
    Oh weird. I had a quadro 4000 and a 5770 and it always felt a little funny running those. I'll prob pick up a 120 when I make then purchase.

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