I built my computer a while back, and I have had this type of issues on and off all the time.

When my computer is actually loading Windows, it works like a charm. The idle temperature is 25-30 degrees (Celsius), 'gaming' temperature is 40-50 degrees and stress test with Prime95 never exceeds 60 degrees.

When I move my computer (I don't know why, but almost every time I attend a LAN-party this problem occurs) it is very little chance for it to load Windows. It usually stops the upstart with a CPU Over temperature failure error (Press F1 to enter BIOS). When I press F1 and enter BIOS, I can see the CPU temperature is somewhere between 95-99 degrees, the odd thing is that the CPU fan speed is 2000-2500 RPM (shouldn't it be more to try fighting the extreme heat?). I have no choice but to power it down and wait for it to cool down. Earlier, replacing the thermal paste has fixed the problem and I could start it normally again.

What happened today was a similar issue... The only difference is that the CPU fan (H80 water cooler) does not appear in the BIOS and the error is CPU FAN NOT FOUND instead of CPU Over temperature failure. I can see the CPU temperature increasing in the BIOS until I have no choice but to power it down again. I can hear and see that the two fans on the radiator is spinning and I can clearly feel, with my hand, that the fans are moving a lot of air.

I plugged the CPU fan in the CHA_FAN2 and one of my chassis fans in CPU_FAN. When I entered BIOS I could see CPU_FAN (which now was the chassis fan) but could not see the CHA_FAN2 (which now was the CPU cooler). Does this mean there is something wrong with the water block (the piece i place on the CPU)?

Is this more likely a BIOS fault or a fault with the water cooler. If it's a BIOS fault, can this be fixed? If this is a water cooler fault, should I replace it?


  • Replacing the thermal paste

  • Take out and in the RAM

  • Clean the radiator for dust

  • Switching the CPU and the chassis fan connector

  • Checked that there should be no problem for the water to flow in the tubes between the radiator and the water block

  • Waited before a restart (so there was time for it to cool down)

I appreciate your answer! -Espen

  • Did you add anything to the water to prevent build up of minerals? Build up usually occurs inside the CPU block. I had to use CLR once to clear the build up since I wasn't using anything to kill the micro organisms in the water. Is the water distilled? – cybernard Jul 21 '13 at 16:09
  • I have not added anything to the water. The H80 is a closed water cooling. I have not filled in the water or replaced the water. Can I do this on a closed water cooling block, and will it void warranty? Thanks for the reply. – Espen Jul 21 '13 at 20:54
  • I have taken out the H80 system and tested it with only the PSU and the H80. I used a heat gun (at safe distance, of course) to slightly heat up the block. The fans started to spin faster, but there was no cooling effect on the block. After that I installed the stock fan and my computer can boot normally. I guess I should return the H80 system to Corsair then? – Espen Jul 21 '13 at 20:58
  • If it is still under warranty I would say "yes". If you shake the radiator can you hear the water in the radiator? – cybernard Jul 21 '13 at 22:26
  • I had a GPU water block once and half the water evaporated in 6 months and had to refill it. – cybernard Jul 21 '13 at 22:51

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