GeForce 9800 GX2 in Mac Pro (Vista 64)

Discussion in 'Mac Pro' started by barefeats, Mar 28, 2008.

  1. barefeats macrumors 65816

    barefeats

    Joined:
    Jul 6, 2000
    #1
    I installed the BFG GeForce 9800 GX2 in our "early 2008" mac pro 3.2GHz this morning. It requires two power feeds - one 6 pin and one 8 pin. I used the 6 pin to 8 pin adapter that came with the card to plug into the 8 pin connector. If the green lights come on, you have adequate power. If red lights come on, you are in trouble. I had green lights. Yay.

    I booted Vista 64 and installed the latest drivers from nVIDIA. It runs Windows 3D Games faster than any Windows PC compatible card I've tried (including the GeForce 8800 GTX OC and Radeon 3870 X2 OC).

    Crysis:
    47 fps at 1280x800 High
    59 fps at 1920x1200 Medium

    Unreal Tournament III:
    Suspense Flyby at 1920x1200 Best Settings = 154 fps

    Prey:
    Prey Demo000 at 1920x1200 High (8X aniso, shadows on) = 210 fps

    Of course, it does not boot OS X. And it draws too many watts to run with any other card but the Radeon 2600 XT. In that scenario, you would boot with the Radeon to run Mac OS X and boot the GeForce to run Windows. But the fans on the GeForce will probably be running full blast when you are running Mac OS X. We'll let you know since we will try that next.
     
  2. Tallest Skil macrumors P6

    Tallest Skil

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    Aug 13, 2006
    Location:
    1 Geostationary Tower Plaza
    #2
    Congrats... but it'll be outdated by the time Nehalem* rolls around.:p Now... could you answer me this: How many places are there to plug in PCIe external power cables inside the Mac Pro? Are there just two, put there for the Quadro FX 5600/Two 8800 GT setup, or are there more? Thanks!

    *GeForce 10800 GT as the mid-range card in the Nehalem Mac Pro. You heard it here first.
     
  3. Firefly2002 macrumors 65816

    Joined:
    Jan 9, 2008
    #3
    Isn't there someway to disable the primary card in the EFI before you boot into OS X?

    Lol. Yeah right. The 10.8 won't even be out... assuming they even call it that. Notice how ATI went from 9800XT-->X800XT to avoid the 10000 number? ;P
     
  4. Tallest Skil macrumors P6

    Tallest Skil

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    #4
    In all actuality, I was going to put X800 GT, but it didn't feel right...
     
  5. Brianna macrumors regular

    Joined:
    Feb 8, 2008
    #5
    That's cool. Does windows recognize that as two GPU's or one?

    I read somewhere that the 7950GX2 was recognized as one GPU by the OS.

    Can you try nvflash --check on it to see what the firmware looks like?
     
  6. Brianna macrumors regular

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    Feb 8, 2008
  7. aLoC macrumors 6502a

    Joined:
    Nov 10, 2006
    #7
    I have a 9800GX2 in my gaming PC (not my Mac Pro) and it shows as 2 GPUs in Windows.
     
  8. SuperGrobi macrumors member

    Joined:
    Feb 16, 2008
    #8
    Humh, is this good or bad for chances to run the 9800GX2 as two "8800GTs" in OS X? :confused:
     
  9. ildondeigiocchi macrumors 6502a

    ildondeigiocchi

    Joined:
    Dec 30, 2007
    Location:
    Montreal
    #9
    The Mac Pro doesnt have an Eight Pin Power connector so how were you able to install the card. i really want to know because i am planning on getting the GX2 also. Another thing the Mac Pro only has a 300W Power Supply for graphics cards and the 9800 GX2 requires 450 W. so how were you able to install it. Please let me know. :)
     
  10. Mercuric Oxide macrumors 6502

    Joined:
    Jan 6, 2008
    Location:
    NYC
    #10
    450 is the total wattage of the system when using the GX2, not the card itself.

    The card alone is about 230 watts peak.
     
  11. ildondeigiocchi macrumors 6502a

    ildondeigiocchi

    Joined:
    Dec 30, 2007
    Location:
    Montreal
    #11
    So will it short circuit the computer or not?
     
  12. Pressure macrumors 68040

    Pressure

    Joined:
    May 30, 2006
    Location:
    Denmark
    #12
    Most likely from the optical bay but given that the Mac Pro has a 1kWh+ power supply it can easily power the Geforce 9800GX2 if you can route the cables to it.

    The 300 Watt limitation is coming from how many watts the logic board can supply through the total number of PCI-Express slots.

    No.
     
  13. barefeats thread starter macrumors 65816

    barefeats

    Joined:
    Jul 6, 2000
    #13
    Kaboom!

    The 9800 GX2 comes with an 8 pin to 6 pin adapter. The 9800's documentation says that if your power supply is strong enough, you simply connect one of the 6 pin cables to the 8 pin adapter. The 9800 indicates with a green light at both ends if it has enough power. And with the Mac Pro, it does show green and boots Vista 64 nicely.

    According to hardocp, the 9800 GX2 consumes 268 watts under load. The PCIe bus only tolerates 300 watts total load counting all slots. So that only leaves 32 watts for any other cards.

    However, I figured if no display was connected to the 9800 GX2, it would idle at 99 watts (hardocp info). But, when I tried to boot the Mac Pro using the Radeon HD 2600 XT (50 watts) connected to my display and the 9800 GX2 powered up but disconnected, I get a kernel panic. Ditto for the GeForce 8800 GT OEM card (110 watts) from Apple. So much for my theory.

    So the way I see it, the GX2 is not a realistic option for the Mac Pro since you would have to remove it physically each time you boot Mac OS X. And believe me, it's a tight fit and very hard to remove.
     
  14. giantsfan1975 macrumors newbie

    Joined:
    Mar 31, 2006
    #14
    I second that..

    I bought one and tried it last week. I received a kernel panic upon boot with the 8800 and the 2600.

    I would like someone to make a silent cooler for the 3870x2 so I can use it in the MP along with the 2600 or 8800. The 3870X2 fan under OSX is seriously loud and I don't want to have to use a fan adjusting switch or tinker with it otherwise.

    Ack.. Did I just say I want an ATI card? Bleh..
     
  15. SuperGrobi macrumors member

    Joined:
    Feb 16, 2008
    #15
    So the only chance left is that some gifted Mac user will manage to make the 9800GX2 run in Mac OS ... like using a modified 8800GT rom? I think the chances that Apple will offer a faster alternative to the 8800GT is close to 0 ... mainly because of the power consumption :(
     
  16. SuperGrobi macrumors member

    Joined:
    Feb 16, 2008
    #16
    Maybe a stupid idea, but is it simply possible to unplug the additional power supply of the 9800GX2 ... and boot using the HD2600XT? Or will the Mac Pro not boot if the card reports low power???

    Damn ... I would love to use the 9800GX2 in the Mac Pro but I don't want to remove it everytime I boot Mac OS.

    Well, maybe it is time to think about a "gaming PC" :(
     
  17. pastrychef macrumors 601

    pastrychef

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    Sep 15, 2006
    Location:
    New York City, NY
    #17
    Maybe an external power supply to feed the 9800GX2 would work...
     
  18. statikcat macrumors 6502

    statikcat

    Joined:
    Mar 20, 2007
    #18
    Does OSx boot ok with this card in? I assume it just ignores it?
     
  19. barefeats thread starter macrumors 65816

    barefeats

    Joined:
    Jul 6, 2000
    #19
    Tried that. Still can't boot OS X with any other card present.

    Odd because the Radeon HD 3870 X2 -- which draws more wattage than the 9800 GX2 -- happily co-exists with the Radeon HD 2600 XT in my Mac Pro "Harpertown." I boot OS X with the 2600. I boot Vista 64 with the 3870 (or the 2600 or both).

    If you run pro apps under Mac OS X and run 3D games under Windows, the 2600/3870 combo is the best current setup.
     
  20. j1nxy macrumors newbie

    Joined:
    Apr 2, 2008
    #20
    Hi

    When you run this combo I assume you have both cards installed at the same time? If so what slots are they in and is the 3870x2 silent while your in OSX?

    Thanks

    Steve
     
  21. aLoC macrumors 6502a

    Joined:
    Nov 10, 2006
    #21
    This really is the best idea. I have two towers side-by-side under my desk, a Mac Pro and a gaming PC. One major advantage over a dual boot system is you don't have to shut down OS X all the time. Also you can buy the latest video cards without waiting for Apple.

    Until such time as Aspyr starts porting A-list games in reasonable timeframes, and until such time as Nvidia provides up to date Forceware for OS X, this will remain my setup.
     
  22. Siron macrumors 6502

    Siron

    Joined:
    Feb 4, 2008
    Location:
    North Carolina
    #22
    Barefeats I have a question. I assume the power consumption problem is related to the 300 watt limit of the PCIe slots. Now I'm a complete novice when it comes to Macs (I've built many a PC) so I need to understand how the video cards get their power. On a PC with older cards they were powered from the PCIe (or AGP) slot. I've installed newer cards in PCs that, because of their power requirements required a secondary source via a Molex connector fed directly from the power supply.
    I looked in my MP and there is a cable from the video card that plugs into a connector on the MB. Is this a secondary power supply (akin the to Molex on a PC) or is this the only supply?. As the 9800GX2 has a separate power cable is it possible to connect it to the spare power connector in the optical drive bay thus circumventing the 300 watt limit. I'm sure you've thought of this but I'm curious as to how the MP is configured.
    Thanks
    Alan
     
  23. SuperGrobi macrumors member

    Joined:
    Feb 16, 2008
    #23
    I am not an expert, but as far as I understood the whole problem maximum 300W are delivered through the PCI slots ... the additional power that the card draws from the external source is not part of this calculation. So it does not matter where you put in the plug ... still the PCIe slot is the limiting factor ... correct me if I am wrong. ;)
     
  24. Siron macrumors 6502

    Siron

    Joined:
    Feb 4, 2008
    Location:
    North Carolina
    #24
    I can't imagine that the cards draw most of their power from the PCIe slots. I am assuming that the power cable plugged into the MB (analogous to a PCs Molex connector) is because the PCIe slot doesn't provide enough .
    However I am not Mac expert so maybe Barefeats can answer for us.
    Alan
     
  25. adrianofmaia macrumors newbie

    Joined:
    Sep 19, 2008
    #25
    Hello Barefeats,

    I believe you may be interested on this (start to read from post 17):

    http://forums.macrumors.com/showthread.php?t=465792

    I not only got OSX to boot on my macpro with the 9800gx2 connected. But also managed to make it recognize, load drivers and I am using as my video card on OSX 10.5.5 on my real mac pro (not hackintosh).

    Hope it helps someone. I post all my progress. :D
     

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