Bitcoin Forum

Ive noticed now that its really hot out, a lot of my LTC mining rigs running much hotter and some of the cards are hitting 100-103c and begin to thermal throttle. The effect is that the hashrate goes down, because if I add external cooling (extra fans etc) the hashrate goes back up to around normal when the cards are at 80-90c.

So basically I need a lot of external fans to keep my cards at a high hashrate, but Im wondering how much of the heat is related to scrypt rather than SHA256 mining, and what you experiences are with thermal throttling, GPU fan death and heat related component failure, and overall the best way to run rigs in the heat.

Right now I have a 80mm case fan on one of my GPUs that had its fan die, its works OK but still not as good at the OEM fan + shell which seems odd.

I don't understand how it's possible for you to get a GPU to run at 100*C. Do you overvolt the cards, run them in a sealed styrofoam box, and set the fan speed to minimum?  :D

I've been running my 7990 Cards at 100c.  They have been running for almost a month at that temperature.  They seem to like the heat!  Haven't had to reboot yet!

I have run my 7950s at 90 before.  They never missed a beat.  But I felt bad for them.  I bought separate box fans for them and now they cruise at 67 and 76, respectively.  I would get that temp down if I were you.

Powercolor 7950's have the worlds shittiest cooler on it...

Looks like an overgrown Pentium 4 cooler with no heatpipes at all.

They regularly hit 90-100c bitcoin mining... they throttle down if they spike to 102c also... but never lockup the machine. *shrugs*

I hope they die so I can send them back and hope they send me something that has a proper heatsink on it.

Don't, 100C is the maximum safe operating temperature. You're hitting the card's thermal limit. More fans is the best option, otherwise you can fit watercooling but I don't think it's worth the expense. If you haven't already you can manually set the GPU fans to 100%.

My Sapphire 7950s run up to about 90C overclocked with the lousy stock cooler but I suspect I live somewhere cooler than you do (62 out right now).

What the Hell, guys... undervolt that shit. Blow the inch of dust off the heatsink. Plug the case fans back in. Take it out of your attic. >90*C 24/7?

100*C is the point where hardware failure is imminent on these. Just because there's a thermal limit doesn't mean you can run it 5*C under the absolute maximum 24/7/365. Just because throttling doesn't kick in doesn't mean it's safe. GPUs have one key advantage over ASICs, and it's a big one -- GPUs have great resale value relative to ASICs and FPGAs. Even if cryptocurrencies become a historical footnote within the next few years, GPUs still have a market. Don't throw that away for a few pennies more a day in revenue.  >:(

Previously I rented a place in a datacenter, that makes life easier and manually fixed the GPU fans so that the temperature is about 60 degree celsius.  If you are into the 100s, you are going to shorten the life of your cards a lot.  No point, at least try to get them running until ROI.

Don't matter really, b/c if the card fail, just RMA it.
Most cards come with 2 yr warranty.

XFX comes with lifetime  ;)

As others mentioned before, your cards shouldn't really go up to 100 ºC. What GPUs? How are they mounted? Clocks? Miner settings?


That depends. Chances are, you won't be able to mine a scrypt-based coin at the same core clock than a SHA256-based coin, but you'll need a higher memory clock and a higher intensity.

Advantage of SHA256: You can underclock the memory to 300 MHz and still get the same hashrate.
Advantage of scrypt: Since the memory clock will be more limiting than the core clock, you can undervolt the GPU (if your card permits it).

Both method can lower the operating temperature dramatically.


I don't let my GPUs go over 80ºC. I also limit the fan speed; you can't really go by the percentage, since one card's 60% might be another card's 100% (rule of thumb: if it sounds like a jet engine, it's going too fast). So far, none of my equipment failed.


If you can, build an open case.
Make sure all your fans are clean. Removing the dust from one of the case fans lowered my temps by 5ºC...
For SHA256, using CGMiner's built-in GPU throttling is straightforward. Specify a target temperature, and it will underclock your GPU if it starts to run too hot. Since clocks for scrypt are deep magic, I'm not sure if automatic clocking is a good idea.

whats the command for this? (sorry for the hijack)

I felt bad for them :) lol

I feel bad about mine too , so I keep them at 62-68 temps

My 7970 windforce at 100% fan rarely leaves the 88-90 degree range with 26-28 ambient. The room it's in has terrible ventilation tho so rarely drops below 25!

This is with fans blowing in cool air to the general intake zone of the card, and two fans on the back of the card which help with the vertical exhausting of this card. Open rig too! Without the extra fans it was hitting 95 which is far too high. 1085/1500 scrypt.

dude... 100c!?!?!? please ship those cards to me, I wont abuse the fuck outta them!

If your cards ever go over 85C, you are doing something wrong, IMO.

Stock 7990 cards all run at over 100c when you first put them in.  I wonder if I can under volt the7990 cards.

Anyone know of a solution?

You have to specify a target temperature, a core clock range and enable "auto GPU".


If you underclock your memory with Afterburner, leave the memory clock alone. Otherwise, set the difference between memory and core clock the minimum allowed by the driver:

100% fan is also bad, mkaaay?
You wear down those, and everything in the last 15% of max fan speed does not add that much to cooling process.

 Have you downclocked your memory as low as it will go ? Try taking it down to 685 (or lower if you can), and that should allow it to run cooler.

 Don't need your VRAM clocked high while hashing... unless you are doing Scrypt stuff, then, well, yeah, I guess 100C is possible.

I think what you are referring to is the reference 7950 cooler, it has a vapor chamber but as you say it is quite useless. Only good thing is that the cards with those coolers should also come with the reference PCB and guarantee that the cards aren't voltage locked

I'm mining Litecoin so yes I need scrypt.. :(  But it's been running for a month now non stop.. I guess I'll run it til dead, two year warranty.