[Tech help] PC keeps turning itself off

[2000AD]

Been having problems recently where my PC will randomly just turn it's self off. Not shut down, just straight away, *Bzzuuuuuummmm*, power goes off.

Only seems to happen when playing certain games as well. I can play Battlefield 2 and Football Manager just fine, but Call of Duty 4, Team Fortress 2 and Warhammer Online cause it to crash (CoD4 more than any other game).

Anyone any ideas what might be causing it?

[The Grim Squeaker]

Check the fan for your graphics card, and the fan on your power supply. clean out any dust (after turning the pc off)

This happened to me once, when the fan on my old GPU died, play something too intensive, it heats up and the rig shuts down to prevent it melting.

[2000AD]

Eeeeek! Downloaded a core temp monitor.

My idle temperature was between 84-86 degrees centigrade for each core (quad core), but when i loaded up Warhammer Online it went to 125-127.

That answers what the problem is, now the cause. Looking in the side while I was rebooting there looks to be a layer of dust underneath the big fan on top of the CPU, guessing that;s the cause.

[Vendetta]

Probably also worth taking the fan off, cleaning it and the CPU die, and applying new thermal paste.

[2000AD]

Well, used some compressed air to clean the dust off of the CPU fan.
Temperature when i loaded it up was 62-63 centigrade across all 4 cores.

Testd by loading up Warhammer and it initially jumped to 75 degrees, then started creeping up at the rate of about 1 degree every 10 seconds. Turned off Warhammer when it hit 90 and it's now cooled down to 62 degrees again.

So cleaning the fan appears to have worked a bit, but I'm guessing those temperatures are still high.
Time to look into new thermal paste.

[Braedley]

62 is still really warm for idle. My CPU typically idles at less than 45C, and I have el cheapo stock heatsink and fan. Under full load, it might reach 80, but I've never really tested it.

[erik_t]

The effect of thermal paste is profoundly overrated. Unless the stuff is ten years old and dried out (which of course it's not if you have a quad-core machine!), then changing compounds will make not a lick of difference.

This is an enlightening read.

If you're not crashing, then your CPU temperature is not worth fretting over. The folks who implemented the omg-too-hot-better-shut-down routine know a lot more about the processor's thermal properties than we do. If it still bothers you, then get a big beefy fan. Heat sink compound won't make a lick of difference.

[2000AD]

Well it was crashing, and while just cleaning the dust from the fan reduced the idle temperature by 20 degrees, it's still high at 60-65 degrees and it seems I can't run any game that doesn't need Dosbox to emulate, even internet based flash games send my temp creeping up to 100 degrees.
So I'm getting new paste and a new fan and then hopefully normal service will be resumed.

[Edi]

The effect of thermal paste is profoundly overrated. Unless the stuff is ten years old and dried out (which of course it's not if you have a quad-core machine!), then changing compounds will make not a lick of difference.

This is an enlightening read.

If you're not crashing, then your CPU temperature is not worth fretting over. The folks who implemented the omg-too-hot-better-shut-down routine know a lot more about the processor's thermal properties than we do. If it still bothers you, then get a big beefy fan. Heat sink compound won't make a lick of difference.

Some thermal paste compounds are absolute shit because they are so thick that they are impossible to apply in the correct (reasonably small) amount. You don't need a whole lot of thermal paste, just a thin film. The thick compounds act as de facto insulators and cause heat problems instead of solving them. But it's a matter of quantity, not of quality.

[erik_t]

Specifically what do you have in mind? I've never seen thermal paste (well, not in the last decade at least) that wasn't perfectly serviceable.