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Title: 4x7950 rig, unequal heating Post by: thehun on January 08, 2014, 05:04:20 PM I have mounted the following rig:
http://img571.imageshack.us/img571/2537/zuv3.jpg 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. http://img542.imageshack.us/img542/7810/m367.png I am running the fan of GPU 3 at 95% already. Any tips on why it could be getting so hot? Title: Re: 4x7950 rig, unequal heating Post by: mikeybit on January 08, 2014, 05:18:25 PM 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. Title: Re: 4x7950 rig, unequal heating Post by: thehun on January 08, 2014, 05:26:59 PM 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... Title: Re: 4x7950 rig, unequal heating Post by: mikeybit on January 08, 2014, 05:44:24 PM 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. Title: Re: 4x7950 rig, unequal heating Post by: SpeedDemon13 on January 08, 2014, 05:50:32 PM Only suggestion it to separate them apart a little more and add a spot fans to cool them or water cool them.
Title: Re: 4x7950 rig, unequal heating Post by: rwessels on January 08, 2014, 06:41:08 PM 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.
Title: Re: 4x7950 rig, unequal heating Post by: mikeybit on January 08, 2014, 07:33:00 PM 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. Title: Re: 4x7950 rig, unequal heating Post by: thehun on January 08, 2014, 07:50:56 PM 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 :P. 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 :-) Title: Re: 4x7950 rig, unequal heating Post by: thehun on January 08, 2014, 07:53:09 PM 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 :-\ Title: Re: 4x7950 rig, unequal heating Post by: thehun on January 08, 2014, 07:53:56 PM 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... Title: Re: 4x7950 rig, unequal heating Post by: kalus on January 08, 2014, 08:28:22 PM 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 |
