two 7970s

Printable View

02-03-21, 01:55 PM
MindCrime

1 Attachment(s)

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
Attachment 3115
02-03-21, 03:20 PM
Al

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.
02-03-21, 04:04 PM
MindCrime

Re: two 7970s

Quote:

Originally Posted by Al

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...
02-03-21, 05:29 PM
DrPop

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.
02-03-21, 09:49 PM
John P. Myers

Re: two 7970s

Quote:

Originally Posted by DrPop

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
02-05-21, 02:07 PM
MindCrime

Re: two 7970s

Quote:

Originally Posted by John P. Myers

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.