My PC has the fans controlled by Speedfan to maintain the CPU temp under 80°C. Trouble is it's been tending to crash occasionally on me...

PC spends a lot of it's time running Folding@home on the CPU and GPU, i.e. 100% load on both. Not as bad as Prime 95 + Furmark but not far off.

Yesterday I noticed that Speedfan wasn't changing the figures and found it was non-responsive so I killed it and loaded it again.
Now my PC runs around 300w AC under folding load and Speedfan is set to run fans at 25% idle and up to 75°C CPU temp, 75~80°C is 50% fan speed and 100% over 80°C.
It tends to cycle between the 25 and 50% settings but isn't particularly noticeable or annoying, most of the time, in it's doing so. I think it had set the fan 25% and then crashed so didn't raise them as needed. As I'm crazy I've attempted to recreate the situation for you viewing pleasure!


In fact I think I caught a glance of one of the CPU cores at 99°C, which would be throttling temperature! PC hadn't crashed though nor was it acting up and doesn't seem I've done any harm.
In the above shot I don't think the CPU was even throttling, the PSU fan is way above normal due to extreme heat under it cooking it's casing and the hot air it would have been tending to draw in.
Speedfan, once working, shoved the fans to 100% and fairly quickly brought the temps back under control.


I've now updated Speedfan and will keep an eye on it.
Regards, Seb

The only component which can really suffer from such situation is the hard drive. CPU or graphics card doesn't mind the high temperatures - they either throttle or shut down.

Speedfan did f*ck up for me too.

It stopped adjusting the fan speeds. But the app stayed responsive.

Never found out what it was, because happened to reinstall Windows the next day. Now it's working again.

I do have a BIOS CPU warning temperature set though, that makes a ghastly noise if the temps get serious (70°C for me) and is totally independent of Speedfan.

This happened to me once with an older version of speedfan (in 2005 in think...), where it froze, but set the fans up to 100% in the process (also it was 3 am and it scared the crap out of me, I didn't know anything about quiet fans at the time, and those 2500rpm 80mm fans can be noisy buggers) !!! Anyways, the rest of the readings seemed fine. A reboot fixed the problem and I've never had a problem after that.
However, when I started messing around with the quiet and folding@home issues, I decided to go all hardware and forget about software fan control : one fewer point of failure is always better. I keep speedfan around but it does do anything for my fan speeds, and since temps are pretty much flat (folding keeps them up ) I don't see any reason why fan speeds should vary.

I just use CoreTemp with the BIOS fan controller.