Non-EFI/OSX GFX cards in a Mac Pro

Discussion in 'Mac Pro' started by Axonometry, Aug 13, 2008.

  1. Axonometry macrumors newbie

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    Jun 30, 2008
    #1
    Okay, so lets summarize what happens when you boot into OS X while a standard PC (non EFI) graphics card sits in one of the PCI slots (assuming you have another one plugged in that is OS X compatible)...

    We know that the fan on the PC card starts to spin at full throttle.. Because the fan control — which resides in the ROM - isn't loaded due to the BIOS/EFI compatibility issue (I'm not sure why apple chose EFI in the first place, but if they wanted to brutally limit the graphics hardware we're able to use in our macs, they succeeded...).

    Okay, so by the time you boot OS X, the PC card is dead. Nothing is loaded from its ROM, the motherboard and the OS doesn't even recognize it. But the fans have gone wild, uncontrolled, because this is the normal safety behavior, so the chip on the card wont fry if something goes wrong. If I understand this correctly, the card is not used, no data flows through it, the chips/memory on it is as cold as ice.



    So what if you disconnect ONLY the FAN on the card (if its possible on that very card), when you are about to boot into OS X (which, I think is the major reason we've bought a MAC pro, not some PC..)??? It wouldn't damage the card, would it???:confused:

    Furthermore, what if you buy a card with passive cooling??? I've seen a 3870 from sapphire with passive cooling which is also great for obvious noise reasons. How would that behave in a twisted situation like this???:confused:


    I'm aware that this issue has been discussed numerous times here, in a lot of threads, but I wanted some summarization from the people who have clear insight of the whole problem.

    After all, we all bought Mac Pros to use OS X on them for the most time, and I think I speak for a lot of people when I say we shouldn't endure the loud fan noise / and of course the reduction of the life span of the given cards cooling apparatus, in favor of some occasional Windows gaming.

    Cheers
     
  2. Pressure macrumors 68040

    Pressure

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    #2
    To put it simple, BIOS is something that needs to be buried and the world+dog should adopt EFI faster than they can say it (Extensible Firmware Interface, that is).

    The card is still using power even if it is not recognized. If you disable the fan you will have one burned card at some point. It will be going at full throttle with no power optimizations enabled.
     
  3. Axonometry thread starter macrumors newbie

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    Jun 30, 2008
    #3
    But why would it generate heat, if it doesn't do any work / calculations? So basically, what you say is the card uses power from the motherboard / PSU uncontrolled. And how much power? Do we know this value i.e.. is it the idle or the load consumption?

    So if the chip is not in use, where does the electricity "go"?:confused: It dissipates solely as heat? But how much, can we measure that? Maybe the card can withhold such heat only by using the passive heat sinks?!

    A lot of questions...:confused:
     
  4. Umbongo macrumors 601

    Umbongo

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    #4
    I don't really buy in to this idea that the card suddenly puts itself under full load just because its in a slot, has a power connection and is not recognised by the OS. Why would it do that? Where is the load comming from? Just having a power source surely doesn't mean it's working 100%, how could it?

    The fan control is a very different issue and so the fact the fans spin up isn't an indication of anything to do with what the graphics card is doing.

    I'd definatly interested in getting a definative answer to this.
     
  5. Spanky Deluxe macrumors 601

    Spanky Deluxe

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    #5
    My second 3870, which is a PC only version doesn't spin up its fan to max when I'm in OS X. I don't even notice it, its the fan on my Mac edition that gets noisy sometimes under load. My PC only version only ever spins up when I'm using the two cards in Crossfire mode in Windows.
     
  6. Umbongo macrumors 601

    Umbongo

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    #6
    Does it spin up during startup? That is really what the whole discussion is about.
     
  7. Axonometry thread starter macrumors newbie

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    Jun 30, 2008
    #7
    OK, so it doesn't even spin, or its just not the max? If you look inside the mac pro what do you see? Is the PC card hot (if you can feel that somehow)?

    There must be a lot of users here who use a PC card for gaming only, how do they cope with this fan thing? I doubt they switch cards each time, because of the hassle and the probable damaging of the slot / card. Hearing a loud fan noise all the time, and knowing my hardware is rapidly aging, while working in OS X is not an option for me, and for everyone else too, I suppose.
     
  8. Infrared macrumors 68000

    Infrared

    Joined:
    Mar 28, 2007
    #8
    Yes. However, we can't assume this will be a magic solution for
    us Mac users. Mac specific drivers will still be needed.

    What's more, Mac compatible cards could have two versions of EFI
    firmware in them, one specific to the Mac pre-boot environment.

    In theory EFI could offer better compatibility. The problem is that
    Apple may not be interested in that. They have already shown an
    unwillingness to support the EFI booting of Vista, for example.
     
  9. macz1 macrumors 6502

    macz1

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    Oct 28, 2007
    #9
    It's interesting to know that. Thats how every non-EFI card should behave. Is the GPU cold or does it draw some current?
    Now I'd really love to know if this is also true for a 4870. That's the card which I would like to add in my Mac Pro for Windows games...
     
  10. macz1 macrumors 6502

    macz1

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    Oct 28, 2007
    #10
    Hm, Barefeats seems to put almost every highend GFX card into the Mac Pro under Bootcamp for game tests (http://barefeats.com/harper19.html). Perhaps they can tell us about the behavior in OS X of every card they tested...
     
  11. ceres macrumors regular

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    #11
    I bought an 4850 and it does spin up to too loud levels in os x.
    The same will probably be the case with your 4870. I installed the Zalman VF1000 alternative VGA heat sink and it´s totally quiet now.
     
  12. macz1 macrumors 6502

    macz1

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    Oct 28, 2007
    #12
    Hm, that's not great news, but thank you very much for the info. There is one last thing I would like to know: Is the GPU also running or it's only the fan? Could you please check if the card gets warm/hot when running OS X?
    I wouldn't like a card which consumes ~100W doing nothing...

    Thanks a lot
     
  13. Nik macrumors 6502a

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  14. ceres macrumors regular

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    #14
    It doesn´t draw as much power as under heavy 3D Load.
    I reckon the fan control is implemented in driver software only. As none loads under os x the fan goes full speed.
     
  15. Pressure macrumors 68040

    Pressure

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    #15
    Fan control is part of the BIOS.
     

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