3 DVI displays on 1 Mac Pro..?

Discussion in 'Mac Pro' started by fab5freddy, Jan 16, 2008.

  1. fab5freddy macrumors 65816


    Jan 21, 2007
    Heaven or Hell
    Can i hook up 3 DVI displays on 1 Mac Pro ?

    I will then need 2 dual DVI graphics cards, that are 16 lane ??

    Basically what i am asking is, can i fit 2 whopper size DVI graphics cards
    into 1 Mac Pro ? i think these Grahpics Cards take up too much space to fit
    2 full dual DVi Graphics Cards ?

    Could some please enlighten me if it is possible. THANKS!
  2. newtech macrumors 6502

    Jun 2, 2007
    Depends on the Mac Pro, The MP 1,1 and 2,1 only support one 16X slot but can run a second 16X graphics card, slower, in an 8X slot.

    The MP 3,1 can support two 16X cards in its two 16X PCI-e 2.0 slots
  3. trainguy77 macrumors 68040

    Nov 13, 2003
    Apple even supports up to 4 graphics cards in either of the mac pros built to order.
  4. Random Chaos macrumors member

    Jan 16, 2008
    Well, the latest (2008) variation of the Mac Pro can handle 4 PCI-E cards. It has slots for 2 16x 2.0 and 2 4x. One of the 16x slots has an empty slot next to it, allowing for a double wide card that does not block another slot. The other 16x slot will block one of the 4x slots if you use a double wide card.

    The limitation on driving two high end (8800GT) cards is power. The PCI-E bus is only rated for 300W according to Apple's specs. The 8800GT requires 200W. Since Apple isn't shipping those cards yet, I can't check to see if they are drawing all their power through the PCI-E bus or if they have an external connector. If it is entirely through the PCI-E bus, you're not going to be able to put two in the system, though you might be able to get a 3rd party 8800GT working with a bit of work. Even if it does use an external connector, you might still have issues with the power supply not being powerful enough to drive two of those cards. You might have to hook up an external PS just to power it.

    The Mac Pros can also drive up to 8 DVI monitors using the ATI 2600 cards. There should be no reason you can't mix an ATI card and an nVidia card to get the power of the 8800 on your main monitors and the expandability of more than two monitors (that's my plan, at least). Since the 8800 isn't shipping yet, no one has been able to test to make sure this actually works.

    Just be aware the power consumption requirements of the cards and make sure you don't go over the recommended bus limits and you should be fine.
  5. faumble macrumors regular

    Jan 8, 2008
    I am on the same bus on this thread

    how much power requires the 2600?
    also, which card will be the one used by applications and games? the one on slot 1?
  6. trainguy77 macrumors 68040

    Nov 13, 2003
    The PS is a beast in the mac pros its a 12a power supply at 120v. That won't be a problem. People have run two x1900 with enough power. You just have to wire it into the power connector for the second DVD drive. I would assume its the same for the new Mac Pro.(it does have the same power supply for sure though)
  7. Random Chaos macrumors member

    Jan 16, 2008
    Ok, I'm not finding the original source. Found another source though that lists the 8800GT at only 110W.


    ATI Radeon 2600 XT = 50 watts
    NVIDIA GeForce 8800 GT = 110 watts
    NVIDIA Quadro FX 5600 = 175 watts

    Seems a pretty decent overview of the 3 cards available.
  8. trainguy77 macrumors 68040

    Nov 13, 2003
    I found 75 watts for the 2600. And it depends if we are talking peak or average.
  9. Random Chaos macrumors member

    Jan 16, 2008
    I think I found the original source:


    8800GT: 120W idle; 223W load
    2600XT: 105W idle; 167W load

    This seems high versus other reviews I've seen, and the 4x167W load can't be compatible with a 300W PCI-E bus that Apple has, so it makes me a little questioning of this source.
  10. Random Chaos macrumors member

    Jan 16, 2008
    Found another source for the 2600XT power consumption specs:


    And for the 8800GT:


    Details - Peak wattages:

    8800GT: 271W
    2600XT: 58W

    So technically an 8800GT + 2600GT fully powered would be stretching the limits of the system (330W). However, the idle values (110W for the 8800 and 37W for the 2600) would normally keep it in range. The only time you might have issues is when you're in an intense game with all antialiasing turned on and both cards running at their max. Given that the other sources peak the 8800GT lower, you probably won't run into that issue unless you really push your system.
  11. fab5freddy thread starter macrumors 65816


    Jan 21, 2007
    Heaven or Hell
    well, i guess i don't need a 16 X Graphics Card to run the
    3rd DVI monitor......?

    could i just get a 4X graphics card to run the 3rd DVI monitor ?

    i already have a 16 X graphics card to run my first 2 monitors.....
  12. Chaszmyr macrumors 601


    Aug 9, 2002
    Yes, you can. You can run 3 (or more) displays on any Mac Pro so long as you have any two video cards.
  13. ReanimationLP macrumors 68030


    Jan 8, 2005
    On the moon.
    BTW, the 8800 GT uses a 6-pin PCI-E connector.


    Thanks Engadget!

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