Dual mismatched graphics cards

Discussion in 'Mac Pro' started by stevenz, Aug 3, 2014.

  1. stevenz macrumors member

    stevenz

    Joined:
    Dec 5, 2006
    Location:
    Wellington, NZ
    #1
    I'm in the process of beefing up my venerable octacore 3,1 - and one of the items on the agenda is to upgrade the old nVidia 8800GT card that's in it.

    I've put an EVGA GTX670 card in which is now using both of the PCIe power sockets, but given that it's a 670 I have the usual black screen during the boot process. I've flashed what is supposedly a UEFI firmware to the card which I got from EVGA tech support, but I can't see that it made any difference.

    Now, should I be so inclined, what is the procedure if I were to put either the 8800GT in as well with external power, or something like a GT120 which doesn't need additional power - I would get the bootscreen during the process if the monitor is plugged into the 8800GT or GT120, but if I were to run something GPU heavy, such as (heaven forbid) a game, will it know to use the GTX670 for rendering and the weaker card just for output, or am I going to be causing a massive bottleneck?

    Any recommendations?

    So far the system is up to 32GB RAM, 2 2.8Ghz CPUs, 802.11n wireless, Bluetooth 4.0, SSD boot drive, and USB 3.0 support, so it seems a shame not to beef up the graphics as well to get a couple more years out of the trusty cheese grater.
     
  2. scottrichardson macrumors 6502

    Joined:
    Jul 10, 2007
    Location:
    Ulladulla, NSW Australia
    #2
    I am running a non-EFI GTX660Ti in my main PCI slot, and I also have a GT120 in one of the upper slots. If I plug my displays into the GT120, boot screen is there. Plug back into my 660Ti and I get the black boot screen. I'm really not at all fussed with a black boot screen - I mean, it serves next to no purpose most of the time anyway.

    However, NO, you can't plug your displays into the GT120 and expect the 670 to do all the hard work for games. I am 90% sure it won't work that way.
     
  3. stevenz thread starter macrumors member

    stevenz

    Joined:
    Dec 5, 2006
    Location:
    Wellington, NZ
    #3
    So are you using the GT120 pretty much just for "emergency" purposes?
     
  4. Louis Wu macrumors 6502

    Joined:
    Sep 1, 2011
    Location:
    Toronto
    #4
    I have pretty much the same setup that you have; except I put the GT120 in the bottom slot and the GTX660ti in the second slot. It covers the 3rd slot but I wanted to give the 120 GT some space for cooling. Come to think of it I have a GTX560ti in there now. (needed the 660 for another computer).

    Now I have an ASUS 23" plugged into the GT120 and 2 30" ACDs plugged into the GTX560ti. I get the Apple boot screen on the ASUS and black screens on the ACDs until the system completes the boot cycle. And that is how I expected it to work -- the boot screen is tied to the EFI, and that's on the OEM GT120, so the monitor that's plugged into the GT120 is the one that gets the boot screen... while the monitors plugged into the non-EFI card don't get the boot screen...

    Louis
     
  5. Sharky II macrumors 6502a

    Sharky II

    Joined:
    Jan 6, 2004
    Location:
    United Kingdom
    #5
    Hi,

    I was thinking of doing the same - keeping the GT120 in there for a boot screen on a 24" display off to my side, while adding a PC 7950 as the main card, powering the 30" ACD.

    Thing is, when you run something like FCPX, what happens with regards to GPU power being used, and does it matter which screen you're using?

    Cheers

    Ed
     
  6. h9826790, Aug 4, 2014
    Last edited: Aug 4, 2014

    h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #6
    Why don't you just flash the HD7950 in order to get the boot screen?

    All you need is boot your Mac Pro into Windows (bootcamp or not doesn't matter), get the ROM image by GPU-Z, go back to OSX, run the fixrom script. Boot into Windows again and flash the card with the EFI ROM.

    I am not an expert i this area. In fact, I never do this before I have my 7950. And now, I can OC my card, decrease the voltage, modify the fan profile, and flash the card by myself. The process is not hard at all. Of course, all the credits go to the helpful people here and the netkas forum.
     
  7. Louis Wu macrumors 6502

    Joined:
    Sep 1, 2011
    Location:
    Toronto
    #7
    do you use your 7950 to drive your 84" 4K TV? that's one immense TV!

    one reason I haven't flashed my PC cards is that I'm always swapping cards between computers and want the retain the flexibility to use them as PC cards... no switchable bios...

    but if you're running solely on Mac then I'd say flash away!
     
  8. h9826790, Aug 4, 2014
    Last edited: Aug 5, 2014

    h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #8
    Yes I did, However, the TV only has HDMI 1.4, therefore, it's limited to 4K 30Hz, but it's good enough for me already.

    Screen Shot 2014-08-04 at 22.12.11.jpg LG TV.jpg

    AFAIK, even though you flash the card, it still perform exactly the same in a PC, the EFI part won't do anything, nothing more, but nothing less either.
     
  9. stevenz thread starter macrumors member

    stevenz

    Joined:
    Dec 5, 2006
    Location:
    Wellington, NZ
    #9
    Hmm, looks like it might be worth ditching the GTX670 and replacing it with one of the Radeon's if it's that easy to make them behave correctly. Any caveats there?
     
  10. Louis Wu macrumors 6502

    Joined:
    Sep 1, 2011
    Location:
    Toronto
    #10
    That display is quite something!!

    hmmm. thanks for the info; I might try flashing it some day when I'm feeling adventurous! (but first I want to get a 7970 working in my MP)

    Louis
     
  11. NOTNlCE macrumors 6502a

    NOTNlCE

    Joined:
    Oct 11, 2013
    Location:
    DMV Area
    #11
    In my experience, boot screen is of minimal priority. I used to run a 2600 XT alongside my GTX 660 until I upgraded to triple 1080p monitors. I really don't miss it, but I have it lying around just in case.
     
  12. tyroiii macrumors newbie

    Joined:
    Aug 4, 2014
    #12
    Is there a specific model of the 7950 that you can flash? Or does all of them work?
     
  13. h9826790, Aug 4, 2014
    Last edited: Aug 4, 2014

    h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #13
    I really don't know. As I said before, I never touch this area until I got my 1st 7950. However, from my studying, it seems almost all 7950 can be flashed.

    Anyway, if you plan to do this, you better make sure that you get a 7950 with a BIOS switch, that's much safer when play around with the ROM.
     
  14. tyroiii macrumors newbie

    Joined:
    Aug 4, 2014
    #14
    Thank you. I was leaning towards flashing a nVidia GTX 680, but the 7950 seems to be cheaper used and the 4L looks like it'll be quieter.
     
  15. MacVidCards Suspended

    Joined:
    Nov 17, 2008
    Location:
    Hollywood, CA
    #15
    Non reference 7950s frequently lose HDMI port once flashed
     

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