Results 1 to 6 of 6

Thread: two 7970s

  1. #1
    Silver Member
    MindCrime's Avatar
    Join Date
    February 26th, 2014
    Location
    Portland, OR
    Posts
    940

    two 7970s

    Running two 7970s on one rig (same driver). One is a ghz edition which i've undervolted to 1.125v (it's stable didn't try to go lower) from ~1.215v. The other is a reference at default clocks/voltage. I'm surprised how much cooler it runs even though its voltage is quite a bit higher. Does 75mhz make that much difference? Thinking about undervolting the reference card too.

    Edit: maybe i should redo thermal paste
    7970 compare.JPG

  2. #2
    Administrator
    Al's Avatar
    Join Date
    May 18th, 2011
    Location
    Chapel Hill, NC
    Posts
    6,636

    Re: two 7970s

    Could be a few things. Are the cards right next to each other? Often the lower card's cooling is sacrificed by being butted up against the card above. Lower voltage almost always lowers temps, so undervolting should help. Generally speaking, you should be able to undervolt a bit and be able to leave the clocks at stock speed, but it is card dependent. Lastly, the 7970's have been out for a while, it's possible that the TIM has dried out and needs replacement. I had a Gigabyte 7970 that started overheating and didn't get any better until I replaced the TIM and thermal tape. Again, depending on the card, it can be a pretty easy job or a PITA.



  3. #3
    Silver Member
    MindCrime's Avatar
    Join Date
    February 26th, 2014
    Location
    Portland, OR
    Posts
    940

    Re: two 7970s

    Quote Originally Posted by Al View Post
    Could be a few things. Are the cards right next to each other? Often the lower card's cooling is sacrificed by being butted up against the card above. Lower voltage almost always lowers temps, so undervolting should help. Generally speaking, you should be able to undervolt a bit and be able to leave the clocks at stock speed, but it is card dependent. Lastly, the 7970's have been out for a while, it's possible that the TIM has dried out and needs replacement. I had a Gigabyte 7970 that started overheating and didn't get any better until I replaced the TIM and thermal tape. Again, depending on the card, it can be a pretty easy job or a PITA.
    They are as far apart as i can get them. The reference card is slightly longer and interferes with the right angle (better than up) SATA ports...so i have 1.5-2.0 inch between them. The reference cooler definitely spits its hot air out the back and the xfx card just spills it all over. I'm thinking I'll repaste the xfx card and undervolt the ref card next time i feel like bringing this down. current max is like 73-76c, considering ambient, on milyway on the hottest card..which isn't that hot. Maybe it's one of those don't fix it if it aint...

  4. #4
    Past Administrator
    DrPop's Avatar
    Join Date
    October 13th, 2010
    Location
    SoCal, USA
    Posts
    7,635

    Re: two 7970s

    I remember back when I had two in a rig, JPM said the one that dumps the air back in the case matters, but I can't remember if you're supposed to put it in the upper or lower slot. Maybe he will see this thread and let us know which way it's supposed to be.

  5. #5
    Platinum Member
    John P. Myers's Avatar
    Join Date
    January 13th, 2011
    Location
    Jackson, TN
    Posts
    4,502

    Re: two 7970s

    Quote Originally Posted by DrPop View Post
    I remember back when I had two in a rig, JPM said the one that dumps the air back in the case matters, but I can't remember if you're supposed to put it in the upper or lower slot. Maybe he will see this thread and let us know which way it's supposed to be.
    Yes, the that dumps hot air inside the case should be on top and the one with blower on the bottom. It'll help.

    But he's at 74C which isn't terrible. Could just leave it alone if not planning to OC


  6. #6
    Silver Member
    MindCrime's Avatar
    Join Date
    February 26th, 2014
    Location
    Portland, OR
    Posts
    940

    Re: two 7970s

    Quote Originally Posted by John P. Myers View Post
    Yes, the that dumps hot air inside the case should be on top and the one with blower on the bottom. It'll help.

    But he's at 74C which isn't terrible. Could just leave it alone if not planning to OC
    by chance this is how they are setup. with it being still pretty cold (relatively) i don't care so much right now, but come May ill probably undervolt it and move it to its own box.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •