MacPro 2008 video card question, no not flashing.

Discussion in 'Mac Pro' started by VanneDC, Dec 22, 2010.

  1. VanneDC macrumors 6502a

    VanneDC

    Joined:
    Jun 5, 2010
    Location:
    Dubai, UAE
    #1
    Hi, i just got a refurned Mac Pro early 2008 as a pressy (hugs the little wife) and iam really happy with the config. Its a Oct core 2.8ghz with 12 gig ram and Nvidia 8800GT, wifi, BT dual dual layer burners...

    anywys, while this config is perfect for me in OSX, it does leave a little to be desired in the gaming stakes on win7. Now i have Win7 and i would like to install that on a seperate partition, no dramas there....

    Now my question is:

    I have a 4870X2 card in my pc gming box that i would like to use on the win7 side on my mac pro, however i dont realy care for its use in OSX as the 8800GT is plenty fast enough for anything i do in OSX. I dont realy want to flash the 4870X2 to efi either as iam pretty sure the quarts acceleration doesnt work anyways on that card and i cant be stuffed going through that crappy update everytime a new update to 10.6 comes out as i did with my 4890 on my older macpro 1,1 (which i have sold)

    so i would like to plug the 4870X2 (unmodded) into the main PCIE slot on the mac pro only for use within bootcamp windows 7. and just use the standard 8800GT in osx in slot 2.

    Obviously i want to do this without having to swap card around every bloody time i want to use either windows or OSX.

    is there any dramas with doing this?

    What i am hoping will happen is that OSX will not see the 4870X2 and just use the 8800GT and that windows will only see the 4870X2 as the main card..

    will this work?

    cheers and thanks for any help :)

    oh and also on a side note, how much power will my new 2008 macpro use, ? lots more than my quad G5 that i had a little while ago?

    cheers
     
  2. toxic macrumors 68000

    Joined:
    Nov 9, 2008
    #2
    OSX will see the 8800, Windows will see both.
     
  3. peskaa macrumors 68020

    peskaa

    Joined:
    Mar 13, 2008
    Location:
    London, UK
    #3
    You're going to have a problem with power cables. The 8800GT uses a single feed off the logic board, and AFAIK, the 4870X2 needs a pair of feeds (6+8 for that matter).

    In other words, you need 3 power cables, but the Mac Pro has the capacity for two. My advice would be to ditch the 8800GT entirely and install a GT120 (requires no additional power) for use under OS X, and then the 4870X2 for Windows.

    I'd also note that you'll need to source a 6 to 8 pin adapter.
     
  4. Mackilroy macrumors 68040

    Mackilroy

    Joined:
    Jun 29, 2006
    #4
    I'd disagree with needing a 6-8 pin adapter. My 4890 has that power configuration, but I ran it using two 6-pin cables for months with zero issues.
     
  5. peskaa macrumors 68020

    peskaa

    Joined:
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    Location:
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    #5
    The 4870X2 has a much higher draw than a 4890. It is a pair of 4870s cobbled together, whereas the 4890 is simply a slightly faster 4870. Two 6-pin may work, but I wouldn't like to guarantee it.
     
  6. gpzjock macrumors 6502a

    Joined:
    May 4, 2009
    #6
    3rd power cable available.

    Some modders have used the power supply connector from the spare optical drive bay above the hard drive racks to power their extra GFX cards, the mod can be found on these forums somewhere. A 2008 MP PSU runs about 900w so it has plenty of juice to do so.
     
  7. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #7
    Just to clarify this, the PSU has enough juice to power such a system, if the 12V line that lays in the ODD bay has can supply 150W is questionable, though.

    Personally, I wouldn't power a graphics card via Molex in a Mac Pro. The Pro has a custom PSU and Apple may have decided to make the ODD line just as strong to power two optical drives or a few hard drives.

    There are even people out there who powered a second 5870 from the SATA connectors on the logic board, which certainly don't provide enough power. IIRC, that didn't work well. :)

    Considering that an ODD PSU goes for 30 bucks on newegg, I would't risk the $300 PSU of the Mac Pro.
     
  8. gpzjock, Dec 23, 2010
    Last edited: Dec 23, 2010

    gpzjock macrumors 6502a

    Joined:
    May 4, 2009
    #8
    Limit the juice from the optical drive

    Only 3 power cables are needed, so if 2 are from the PCI-E blocks only 1 needs to come from the optical drive bay and some have even added an extra PSU in the case to cover the extra need.
    These guys put 2 5870s in using 1 cable to each from the optical bay so it should handle 1 in theory: http://www.hardmac.com/articles/331/page1
    If you don't want the risk don't ask the system to do what it isn't designed to do, simples. :D
    Using a PC card is off warranty already tbh. If you have the cash then invest in a 5870 Mac version and run just 1 card for both OS.
    Apple doesn't support that in a 2008 MP either.
     
  9. peskaa macrumors 68020

    peskaa

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    Location:
    London, UK
    #9
    It isn't, as you can just pop it out again, no harm done. Warranty is invalid when you start ripping components out and damaging things, or adding things and damaging the tower in the process.

    Of course, Apple won't actively support you running a PC card, but it won't invalidate your warranty.
     
  10. gpzjock, Dec 23, 2010
    Last edited: Dec 23, 2010

    gpzjock macrumors 6502a

    Joined:
    May 4, 2009
    #10
    Off warranty = not supported, I didn't say it invalidated did I? Sorry if that wasn't clear.
    Modding will invalidate though ofc.
    I use a Sapphire Vapor-X 5870 in my MP '08 but keep a 8800GT Mac version in a box for emergencies.
     
  11. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #11
    That was exactly the article I had in mind. Thanks for posting it.
    I don't want to be offensive to the poster of that article, but powering a graphics card from a single onboard SATA connector is very questionable.
    Those ports are made for powering a single hard drive, hence 10W tops.
    Keep in mind that a 6pin PCIe connector is supposed to deliver 75W.

    Well, apparently it worked for these guys, I'm just wondering how long.

    That's good practice. I always do keep the original Apple parts as well when replacing them with 3rd party hardware. Just in case.
     
  12. VanneDC thread starter macrumors 6502a

    VanneDC

    Joined:
    Jun 5, 2010
    Location:
    Dubai, UAE
    #12
    How are those 5870 flashed? Is It like those 4870/4890's we went through a while back with stuff not working with every update? Cos I don't wanna go through that again. Sucks big time.

    Cheers
     
  13. gpzjock macrumors 6502a

    Joined:
    May 4, 2009
    #13
    I would share your concerns about the power limits too.

    I agree the limits of the SATA lines would be cause for concern. As the article in Hardmac shows , under load their rig draws 355w, with the PCI-E cables delivering 45w each (averaged) and the SATA line delivering 32w. The PCI-E slots themselves only supply around 12w each.
    They consider the SATA line may have a limiter on it hence the splitting of the load across the proper PCI-E lines, I would assume running a HD4870 X2 off 1 PCI-E line and the SATA would probably be feasible unless it had a considerable increase in demand over 2 5870s.
    Like all modding there is an element of risk, which anyone who undertakes should consider carefully.

    My 5870 and its Sapphire 1 GB Vapor-X HD 4870 predecessor have survived every update so far albeit without a boot screen on the 5870. If you are concerned then a Mac version is about £370.
     
  14. peskaa macrumors 68020

    peskaa

    Joined:
    Mar 13, 2008
    Location:
    London, UK
    #14
    Basically yes. Flashing will always have those kind of problems, and is also very dependent upon the card used.
     

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