GTX 295 for Bootcamp, 8800GT for OSX

Discussion in 'Mac Pro' started by punkmofo, Feb 11, 2009.

  1. macrumors newbie

    Joined:
    Jan 23, 2006
    #1
    Hello All,

    I was searching this forum for GTX 295, but I didn't find what I was looking for, it's a pretty new card so no surprise there. I did find a similar topic about the 4870X2 from a couple of months ago, but I'm not 100% clear if the same applies to this card. If this has already been covered in detail, I apologize, and please point me in the right direction:

    I have an early 2008 2.8Ghz, and Vista64 is running great on a separate hd (Samsung Spinpoint F1). I'd like to upgrade to a GTX 295 to use with Vista, and still be able to use OSX. I just want to make sure I have my facts straight. I ordered one of these cables from ATI a while ago, is that what I need to get this up and running? And is there an easy way to keep the 8800GT as well to run Mac OSX (without using the optical drive power) or do I need to replace it with a 2600XT for this setup to work? I'd hate to get rid of the 8800GT if all I need is another cable (or two) to get both cards working.

    Thanks in advance for any advice. Thoughts?
     
  2. macrumors member

    Joined:
    Aug 22, 2008
    #2
    You will require three power feeds for the 8800 + 295 setup. The 8800 requires one 6-pin, the 295 requires one 6-pin and one 8-pin. The Mac Pro only has two PCI-E power connectors on the motherboard, therefore you cannot run the configuration you want off of those alone.

    The ATI solution won't work because you can't run an ATI card and NVIDIA card simultaneously in Windows. The only option I can see working is using the spare molex connector from the optical bay.
     
  3. macrumors 68020

    peskaa

    Joined:
    Mar 13, 2008
    Location:
    London, UK
    #3
    Can you jack power from one of the optical bays if you have a SuperDrive in each? (like in a PC when you run a fan off the molex, as well as the drive), or does that overload the connection?
     
  4. macrumors member

    Joined:
    Aug 22, 2008
    #4
    You could use molex splitter, but I wouldn't advise it. I don't think a single molex cable supplies enough power for a 6-pin connector (molex to 6-pin cables usually have two molex inputs on them), let alone powering a superdrive as well.
     
  5. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #5
    OK, that makes sense, thanks for the reply. Should I be worried about using the connector from the optical bay for the 8800, if I don't need it for anything else? I'm assuming the PSU can handle the load with both cards.

    -- nevermind, I think you answered that above.
     
  6. macrumors 68020

    peskaa

    Joined:
    Mar 13, 2008
    Location:
    London, UK
    #6
    So with the normal set up (ie: single installed SuperDrive) the power comes from a single molex socket on the logic board to the 6/8-pin on the GPU?
     
  7. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #7
    I'm going to try this tonight, I'll let you know how it works out. If I can do it, it must be pretty easy :)
     
  8. macrumors 68040

    Cindori

    Joined:
    Jan 17, 2008
    Location:
    Sweden
  9. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #9
    Well, the good news is I got the GTX 295 running in Windows Vista with no problems. The 8800GT that came with my mac is connected using the optical drive power. The bad news: when I try to boot OSX I get a kernel panic. After trying that I would get a black screen in Vista unless I disconnected power from the 8800GT.

    update: still no luck in OSX. At first I could see both cards in Device Manager. Now I only see the gtx 295 and if I have both cards connected, no picture at all.
    Any ideas?
     
  10. macrumors 6502

    Joined:
    Oct 1, 2008
    #10
    Have you thought about buying a separate PSU for the 295? I'd leave the 8800GT on the native PSU and get at least a 700W PSU to power the 295. Since you won't be able to plug the second PSU into the motherboard you'll need to mod the 24 pin motherboard connector so that you can turn the second PSU on with either the switch on the unit or by adding your own switch. Both options are easy to do. Using the switch on the PSU unit is easier. Instructions. Good luck.
     
  11. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #11
    A second PSU is an interesting idea, hopefully it doesn't come to that. My goal is to dual boot while having the correct card recognized automatically for each OS. I've got this working in OSX but not Vista (this is paraphrased from a thread on the nvidia forums):

    "I don't think it's a power issue. [the 980W PSU] is well within spec to run both cards. After tinkering a bit (updated EFI firmware) I can boot OSX and Windows now with both cards (I'm using Vista 64, not XP). Vista is booting fine, but it seems to be defaulting to the 8800 after running OSX. I tried just switching the monitor cable between cards for a quick check to see which one it's using. In Windows, with the cable plugged into the GTX, I get no image (after using OSX). If I disconnect the power supply to the 8800 and reboot it uses the GTX. OSX now seems to be able to figure it out and uses the 8800GT with power connected to both cards."

    I'm gonna play around with this some more tonight.
     
  12. macrumors 601

    UltraNEO*

    Joined:
    Jun 16, 2007
    Location:
    近畿日本
    #12
    When you get a blank screen, what happens when you tap on the keyboard a few times? By default Windows will use the 8800GT as it's main videocard until such time you tell it otherwise...

    Depending on which version of windows your using, it'll hate having more than one card!! Try disabling the 8800GT in device manager.
     
  13. macrumors 6502a

    IEatApples

    Joined:
    Jan 26, 2004
    Location:
    Northern Hemisphere (Norway)
    #13
    Keep us posted… I'd love to do this myself… if it works. :);)
     
  14. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #14
    Yeah, it definitely does not like it. I don't think I touched the keyboard, I'll give that a shot. I did try disabling the 8800GT and then freaked out when both OSX and Vista didn't boot. After a couple of tries I got Vista to boot in safe mode, then OSX worked again... but that had me worried. I'll try again since I updated the firmware - I don't even know if that's related at all but OSX is booting fine with both cards hooked up since I did that.
     
  15. macrumors newbie

    Joined:
    Apr 24, 2008
    #15
    Keep on runing!

    Hi, what about the 295gtx fan's, are they runing at full power under os x?

    Keep on trying :rolleyes:

    Greetings
     
  16. macrumors 65816

    mattcube64

    Joined:
    May 21, 2006
    Location:
    Missouri
    #16
    Good luck punkmofo, and keep us updated!

    I need a good gaming computer, but need OSX for school stuff. I'd love to get a Mac Pro, but the only way I'd consider it is to be able to install a GTX 295 like you're doing!

    I'm anxious to see if you can get it to work!

    EDIT: And do you mind taking a pic of the interior of your computer. I'd love to see what a 8800 and 295 look like together in the Mac Pro!
     
  17. macrumors G4

    Joined:
    May 6, 2008
    #17
    If anyone is interested in the logic board power cable internationally, look here.
     
  18. macrumors regular

    alam

    Joined:
    Mar 16, 2008
    Location:
    Saudi Arabia
    #18
    tnx :D i'll need those to ship it to my country
     
  19. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #19
    Nope, the fans go full tilt for a few seconds when the machine starts up, other than that they're pretty quiet. The GTX is a little louder than the 8800GT though, which is pretty much silent most of the time.

    No problem, but it'll have to wait a couple of days, the camera's at work right now. I have a giant glowing blue cable going from the 8800 through the top of the optical bay, and the side panel off - until I work up the patience to fish the power through properly (Why is that hole so small?).

    Anyway folks, everything seems to be running. After disabling the 8800GT I installed the 181.22 drivers again, then had to start in safe mode (because that killed everything). Now finally Vista also works with both cards plugged in. I played a few minutes of Crysis Warhead with everything on 'Enthusiast' and 4xAA to make myself feel better. Unfortunately I had to return one of the DVI cables to work today so I just need to pick up a new one for the final test. Sweet. I'll keep you posted.
     
  20. macrumors 65816

    mattcube64

    Joined:
    May 21, 2006
    Location:
    Missouri
    #20
    Awesome, thanks!

    So, does that mean you have both cards installed at the same time. Vista is automatically using the 295, and OSX is automatically using the 8800? No crazy loops you have to jump through?
     
  21. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #21
    I won't know for sure until I pick up another dvi cable. But it is booting both OS's with power going to both cards, which is a step up. I only have one monitor cable at the moment so it's automatically using whichever card I plug it into.
     
  22. macrumors newbie

    Joined:
    Apr 24, 2008
    #22
    Great Try

    Punkmofo, can u post a screenshot of your system-profiler,
    which shows how the 295gtx is listed in Mac OS X?
    Did u modify the drivers of Mac OS X?

    And that I understand u right, under Mac OS X the 295GTX in idle mode is as loud as the 8800gt? unbelievably!!!:eek:



     
  23. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #23
    Not exactly - what I said was "The GTX is a little louder than the 8800GT". It's quieter than I expected for such a huge beast, and not running very hot at all. It isn't any louder in OSX than it is in Windows. It definitely doesn't have the annoying airplane engine whine of the 8800GT which gets really loud as you crank up the speed. I was using rivatuner to adjust the fan speed on the 8800 but I stopped because I was getting some weird results.

    Edit: No, I haven't modified any drivers.

    Here are some screenshots. As you can see, Windows has no problem recognizing both cards. OSX has no idea what to make of the gtx 295. I'm hoping this might change with 10.6.
     

    Attached Files:

  24. thread starter macrumors newbie

    Joined:
    Jan 23, 2006
    #24
    ... I thought it was interesting that the gtx shows up twice in the device manager. Here's another screenshot showing the gtx 295 specs in the appearance control panel.
     

    Attached Files:

  25. macrumors newbie

    Joined:
    Apr 24, 2008
    #25
    Wow

    Thanks for the screenshots,
    I see that u have mounted the 8800gt in Slot 1, and the 295gtx above.

    I think only slot 1 is a the pci-e 16x slot, above there are three slots with 4x and 8x.

    Wouldn't it be better to mount the 295gtx in slot 1 to get the full power of the beast, an mount the 8800 in a 4x or 8x slot??

    I mean this:
    Go to /system/Library/CoreServices/Expansion Slot Utility
    There u can configure the slots.

    Bumble-bee

     

Share This Page