Bitcoin Forum

Hello all,

I have a rig with 3 x 5850s installed. When they're mining, the temperature peak 92-93'C on one of the cards. One of them peak at 82'C and the other one 72'C.

Clock settings & temps

Adapter 0= 775Mhz core, 900Mhz memory | 92'C
Adapter 1= 900Mhz core, 900Mhz memory | 72'C
Adapter 2= 875Mhz core, 900Mhz memory | 82'C

I reapplied thermal paste on the GPUs with Arctic Silver 5 4 days ago but the temps don't seem they've improve much. I am worried that the temp is rising over 90'C. I noticed that some ppl underclock memory down to about 300Mhz.

If I do that, would it improve the gpu temp much?

I can't underclock at the moment yet because I am running catalyst 11.5 and it won't let me set it under 900Mhz. I've heard 11.6 would allow me to underclock but I'd like to hear your opinion first.

The rig is running upright atm 90mm fan has been fitted to blow cool air towards the GPUs from the side.

Specs
Sempron 140 CPU
2Gb RAM
3 x Sapphire 5850s
850W PSU
Asus Crosshair IV Mobo
Ubuntu 11.04

I have looked around the board but couldn't find a specific answer, so if you have any suggestion or advice it would be greatly appreciated. Or if you can share a link with a possible solution, that would be great too.

Thanks in advance!

http://C:\Users\Ei\Desktop\IMG_0245.JPG

Hi

In my opinion you didn't apply correctly the thermal paste or you live in sahara.

For the thermal paste, a thin film is sufficient don't put 0.3cm it is too much.

I have 5850s too OC to 1000/350 and I have 75°C max.

what type of 5850 cards are they? if they're the non-reference designs that doesn't shoot most of the heat out in the back, then the card in the first slot will have the highest temps in most setups. that's because the heat goes upwards, and the this top card will recycle the heated air from all the bottom cards.

as for the memory underclocking, just use MSI afterburner and after you configure your config file, the upper and lower memory limit should be removed. i just posted on how to do that in another thread:

http://forum.bitcoin.org/index.php?topic=30032

I have these cards http://www.overclockers.co.uk/showproduct.php?prodid=GX-259-SP

Will underclocking the memory improve the temp?

The gpus on adapter 1 & 2 saw their temp become lower a bit but not the one on adapter 0. It must be the top one on the motherboard. I'll try running the rig flat to see if it improves.


The thermal paste ain't too thick in my opinion. I just noticed that when I just SSH and check the temps they were all below 75'C but after a while, the temp rises. Does it have to do anything with SSH?

I have the same card (Sapphire 5850 Xtreme)

Try to underclock your memory clock with afterburner. For the SSH I don't think the utilisation rise the temp.

If you downclock the memory significantly, you will notice a drop in temps. But the main reason they have high temps in the first place is because they can't breathe in one mobo. I have two extra fans blowing at my 5850 and 5870, cause the 5850 does indeed go over 90C

Agreed.

SSH will not affect your temps.  RAM clock speed will.  Core clock speed will.

Card voltage makes a very big difference to temperature.  I'm able to get my temps down to 48*C and 35*C for 351 MH/s and 372 MH/s respectively (Sapphire HD5850 Xtreme cards) and a good 10*C of this was due to lowering the voltage below stock.

Good air flow is the most important factor (unless your cards are water cooled then focus on water flow :)).  Think about the air currents in your case and experiment with fan locations and rig orientations (heat rises and has a small effect).  For each test give you rig at least 10 minutes to reach a stable temperature and try to keep the ambient temperature the same for all tests.

The most obvious reason why some of your cards are hotter than the others is because they are all lined up in the case and they are each sucking in air which is being heated by the card in front of it, a Graphics card centipede if you will.

The most effective remedy is to use PCIe risers and position your cards so that they all get good airflow.  If you can't do this then position fans to blow air towards the motherboard inbetween the cards (most cards including yours suck in air from the front and blow it out the sides).

After market cooling is another option but is not as cheap as PCIe risers.  Beware of the coolers which are 3 slots wide because you will then have practically no breathing room between the cards at all (something I learned the hard way).

I agree with dikidera, I have 10x5850's and I use floor fans to cool them down while they are hanging from PCI-E extenders. The hottest I let them get is 85 C. But majority are in the low 70's C.

http://www.target.com/Lasko-Speed-Box-Fan-20/dp/B0014IGKBU/ref=sc_qi_detailbutton

Thanks! I'll run the rig flat and will also install additional (case) fans. Is it better to pull hot air out of the GPUs or blow cooler air towards them?

That speed box fan looks sick. Are you using those fans with your set up? Cheers.