Can 2 4870's fit into a Octo Nahalem

Discussion in 'Mac Pro' started by MnkyPwz, Jul 31, 2009.

  1. MnkyPwz macrumors member

    Joined:
    Mar 6, 2009
    #1
    So after being on the phone with Apple for about 2.5hours I was told that the Nahalem doesn't asupport 2 buss powered Graphics cards. Is this true, or am I missing something.

    I have spent quite some time doing research on the issue of Flashing and what needs I have versus con, and so I bought a 4870. Now I'm told that my Mac Pro only supports one of them. I should also mention that I had purchased a Mac 4870 3months ago with my Mac.

    So whats the deal, is this gonna work, or am I screwed?
     
  2. MacVidCards Suspended

    Joined:
    Nov 17, 2008
    Location:
    Hollywood, CA
    #2
    Why do you want 2 of these?

    There will be no Crossfire.

    You can do it with some power splitters, etc...but not pretty and no real benefit
     
  3. fjf macrumors newbie

    Joined:
    May 27, 2009
    Location:
    U.K.
    #3
    As I understand it there are 2 problems:
    1. There is only 300W supplied total to the PCI slots.
    2. Each of the four slots can supply 75W (thus you can have four GT 120s if desperate). There are also two (and only two) 6-pin power connectors which can supply 75W each - so, for the 4870, you get 75W from the slot and you still need both the provided power connectors.

    So, to run 2 4870s, you need both extra power from somewhere, and extra connectors...

    Technically you could have two Quadro 4800s.

    Take a look at this thread:
    "Running dual 4870's in a 2009 Mac Pro"
    http://forums.macrumors.com/showthread.php?t=665034

    (Apple took 2.5 hours? They answered that one for me in 2.5 minutes.)
     
  4. 2002cbr600f4i macrumors 6502

    Joined:
    Jun 21, 2008
    #4
    Short answer - It can be done, but requires some extra connectors, possibly loss of 2nd Optical drive (since you gotta pull the power from there).

    The bigger issue is that it doesn't really buy you much...

    I needed a 2nd card in order to run extra monitors, so I just picked up a used 2600XT for $75. For OSX use it works fine (although you certainly CAN see the performance difference when moving any sort of window doing OpenGL stuff from one monitor to another when changing cards), and likewise, it works fine in Windows 7, provided I don't try to move anything running DirectX10 from the 4870 controlled monitor over to a 2600XT controlled monitor (since the 2600Xt doesn't support DX10).
     
  5. MnkyPwz thread starter macrumors member

    Joined:
    Mar 6, 2009
    #5
    Because I wanted to have 3 monitors and the PC 4870 is cheaper than the GT 120.

    So what else would you have bought to go with three monitors.
     
  6. 2002cbr600f4i macrumors 6502

    Joined:
    Jun 21, 2008
    #6
    As I posted, pick up a 2600XT used....

    Especially if you have monitors that use DVI inputs... The 2600XT doesn't require AUX power, and supports 2 DVI monitors.

    I run 3 monitors:

    1 Dell 2405 FPW - Hooked to the 4870
    2 Dell 2007 FP - Hooked to the 2600XT.

    Works fine!
     
  7. kntgsp macrumors 6502a

    Joined:
    Jul 27, 2004
    #7

    EDIT: Nevermind. Had a brain fart.
     
  8. fjf macrumors newbie

    Joined:
    May 27, 2009
    Location:
    U.K.
    #8
    Oh, dear. No wonder mine has been crying "Feed me! Feed me!"

    Edit: I'm no expert, and 4870s seem to vary between manufacturers on this, but see:
    http://www.tomshardware.com/reviews/radeon-hd-4870,1964-15.html
     
  9. gugucom macrumors 68020

    gugucom

    Joined:
    May 21, 2009
    Location:
    Munich, Germany
    #9
    If you are unhappy with the performance of the 2600 an 3670 would be an alternative. It will definitely not overload the OD-drive bay power supply. It it kind of pricy though, particularly with a decent cooler on top.
     
  10. TheStrudel macrumors 65816

    TheStrudel

    Joined:
    Jan 5, 2008
    #10
    I believe you mean a Radeon 3870. It has the added bonus of a working analog mini-DIN port, if you need that.
     
  11. gugucom macrumors 68020

    gugucom

    Joined:
    May 21, 2009
    Location:
    Munich, Germany
    #11
    Yes, I meant an ATI Radeon HT3870 Mac&PC Edition. A nice and versatile card but unfortunately with a totally unadequate 1 slot cooler and a slightly heavy price tag if compared with flashed PC cards. Other than that it runs practically in every Mac Pro even when it is crammed with another juice hogging 1st card.
     
  12. rwdds macrumors member

    Joined:
    Jan 5, 2005
    Location:
    Philly
    #12
    Take the new 4870 back! I went thru the same process a few weeks ago. Your onboard Radeon will easily drive 2 monitors with it's two ports (DVI & Mini Display Port). If you want a third monitor get a cheaper PCI graphics card.
     

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