4x7950 rig, unequal heating

[thehun]

I have mounted the following rig:



and for some reason some of the GPUs heat up a lot more than others. I could understand that the one on the edge gets a little hotter, but not a difference of 17° with the coolest card.



I am running the fan of GPU 3 at 95% already. Any tips on why it could be getting so hot?

[mikeybit]

I ran into the same issue with some 280X's.  Mine turned out to be defective.  The cooling pipes were cool to the touch while the GPU was getting to 90*+.  The heat transfer plate and/or thermal paste weren't doing the job correctly.

You could also try undervolting your cards, should save you ~ 10* each as well as some electricity.

[thehun]

I ran into the same issue with some 280X's.  Mine turned out to be defective.  The cooling pipes were cool to the touch while the GPU was getting to 90*+.  The heat transfer plate and/or thermal paste weren't doing the job correctly.

You could also try undervolting your cards, should save you ~ 10* each as well as some electricity.

Thanks,

I have tried undervolting with MSI Afterburner to 1.020V  but I'm not seeing any difference (and cgminer keeps showing 1.250V so I'm not sure if it has actually done anything).

Now I have fixed a case fan to the side of the crate and temp has gone down for most GPUs but GPU3 is still between 88 and 90° 

I really hope the card isn't KO...

[mikeybit]

I ran into the same issue with some 280X's.  Mine turned out to be defective.  The cooling pipes were cool to the touch while the GPU was getting to 90*+.  The heat transfer plate and/or thermal paste weren't doing the job correctly.

You could also try undervolting your cards, should save you ~ 10* each as well as some electricity.

Thanks,

I have tried undervolting with MSI Afterburner to 1.020V  but I'm not seeing any difference (and cgminer keeps showing 1.250V so I'm not sure if it has actually done anything).

Now I have fixed a case fan to the side of the crate and temp has gone down for most GPUs but GPU3 is still between 88 and 90° 

I really hope the card isn't KO...

Some of the 7950's are voltage locked so you might not be able to alter it in Afterburner.  If you do a search, you might find a few ways to either edit the BIOS using a hex editor or flash it to a BIOS that's unlocked.

[SpeedDemon13]

Only suggestion it to separate them apart a little more and add a spot fans to cool them or water cool them.

[rwessels]

I have setups like this, but the key was to not have any one fan blow on another card.  So I mounted two cards on the outsides of the crate (one upside down) so they blow away.  Then I mounted the middle two flat so they were facing up.  Solved all of my temperature problems.

[mikeybit]

I have setups like this, but the key was to not have any one fan blow on another card.  So I mounted two cards on the outsides of the crate (one upside down) so they blow away.  Then I mounted the middle two flat so they were facing up.  Solved all of my temperature problems.

The fans are generally intake fans, but the idea is the same.

I still could not get a 280x I had to not overheat, regardless of how much *COLD* (8*F outside) air was blowing on it.

[thehun]

Some of the 7950's are voltage locked so you might not be able to alter it in Afterburner.  If you do a search, you might find a few ways to either edit the BIOS using a hex editor or flash it to a BIOS that's unlocked.

I have managed to undervolt now using Sapphire Trixx and it seemed to do the trix . Temperatures have fallen to ranges around 70° (75° for GPU3) after reducing voltage to 1.1V (reducing to 1.025 made the system unstable).

However now I have another problem. GPU0's hashrate has fallen to 455KH although all settings seem to be ok  
edit: it was actually because of Trixx that was hogging the GPU. Shut it down and back to normal :-)

[thehun]

Only suggestion it to separate them apart a little more and add a spot fans to cool them or water cool them.

I added two small case fans and all I managed to reduce was a few °C (2° on the hottest one). I have been looking at liquid cooling but it doesn't seem easy nor cheap 

[thehun]

I have setups like this, but the key was to not have any one fan blow on another card.  So I mounted two cards on the outsides of the crate (one upside down) so they blow away.  Then I mounted the middle two flat so they were facing up.  Solved all of my temperature problems.

Sounds interesting, but I think my risers are not long enough to take the cards out...

[kalus]

I have setups like this, but the key was to not have any one fan blow on another card.  So I mounted two cards on the outsides of the crate (one upside down) so they blow away.  Then I mounted the middle two flat so they were facing up.  Solved all of my temperature problems.

Sounds interesting, but I think my risers are not long enough to take the cards out...

then hang them at 90° from how you have them already so you can use the length of the milk crate to space them out.    just give it a shot to see if it works; stability >> pretty