Choosing primary card in crossfire

Hello,
I am using a crossfire set up with my two 6950 2GB's and I would like to know if its possible to change which graphics card is registered as primary. One of my cards has the reference cooler (currently set to primary) and the other is on the 'outside' slot with a better cooler. My primary card is currently having heat issues while gaming due to being cramped with a worse cooler, I feel there may be an improvement if I can make the other card primary.
Due to other things on my motherboard I am unable to change the PCI-E slots that my cards are in.
Is it possible to do this?
8 answers Last reply
More about choosing primary card crossfire
  1. Only way really is to disable the 1 card in Device Manager and your desktop will move to the 2nd card, but will disable crossfire of course.

    To choose your primary card would be to swap PCI-E ports, Which ever card is in the 1st PCI-E will always take the full blow of a game, so if you swap the 2nd card and put it in the 1st PCI-E slot, then that card will be used 1st and more then likely heat up as well.

    Also what temps are you getting on your 6950's?
  2. Could you define heat issues? GPUs are workhorses and can easily take temperatures up to 90 degrees centigrade without sweating. The 6900 series had low total power consumption but the small chips got fairly warm due to their small die size. The 580s were even worse.
  3. Generally speaking the primary card is based on what PCI-E slot the cards are in. You could switch the cards around and see if that helps. However reference coolers are notoriously crap and it may not actually help your temps that much.
  4. Heat issues meaning that my primary GPU sometimes overheats and my computer shuts down (It runs much hotter than the secondary card). I am unable to switch their position due to my sound card also being on the MOB (I can not physically fit the two GPU in if I swap their position). Is changing the position the only way to change this?
  5. It's the only feasible way that I can think of. Sounds to me that you need to pull the reference card out and re-seat the heatsink. Apply some new thermal paste and make sure you're fan is operating properly. The HD6xxx series cards have a max TDP of 105c, and if your exceeding that temp (which you shouldn't) then it sounds like either its your fan or you need to re-apply new thermal paste and give that a try.

    What are you temps? Is your card overheating under normal load (ie non-gaming)?
  6. Idle temps:
    Reference cooler card: 60c idle
    Newer card w/better cooler: 40c idle
    Is that normal or would you recommend the thermal paste/heatsink tweaks
  7. 60c at idle is definitely high for that particular card even with a reference cooler. I would absolutely re-seat the heatsink and see if that solves your problem.

    Also take a look at your case airflow, make sure you have enough positive air flow to get the hot air out.
  8. Slayersc2 said:
    Idle temps:
    Reference cooler card: 60c idle
    Newer card w/better cooler: 40c idle
    Is that normal or would you recommend the thermal paste/heatsink tweaks


    60 idle is a bit too high for that card. It should be idling in the 45-50 range at most even with poor cooling.

    If your GPU is overheating and shutting the PC down you have a bigger problem
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