CPU spiking to 89c in bios, mobo at only 21.

calebl2017

Prominent
Aug 27, 2017
4
0
510
So over the last week, I've been dealing with a weird overheating issue with my CPU. All I have to do is turn my PC on and sit at the bios, and it'll go from about 20-25c, all the way up 89c in about 30 seconds, then just sit there lowering my clock speed and voltage until it shuts itself off. Meanwhile, my motherboard only just barely goes over 20c, and my graphics card does just about the same.
I can't even make it to my windows login screen before my PC claims it's overheating, then shuts itself off.

I've tried replacing the thermal paste a couple times, buying a new AIO water cooler, and did some troubleshooting for just about anything I could find info on when I searched the Internet. I was told it could be a virus of some kind, but I'm not sure considering it starts getting hot in just my monitor page for my bios.

I've got an i5-6600k, sitting on an ASUS Z170 Pro Gaming motherboard, with a Corsair H60 AIO water cooler, which replaced my old Asetek 550LC.

If anyone's got any ideas or tips they can give, that'd be great.

Edit: Just thought I would also note that the fan for the Corsair H60 isrunning, and you can hear the water flowing if you really get close and listen. Plus the cpu is for sure making contact with the heatsink, so it should be cooling..
 

calebl2017

Prominent
Aug 27, 2017
4
0
510
Well I replaced the original cooler, and I've double and triple checked that the new one is definitely running. Water is flowing, the heatsink and radiator are still cold, fans are all running, etc,.
 

calebl2017

Prominent
Aug 27, 2017
4
0
510
So I've just gone and replaced the thermal paste one last time, and also dug up my laptop and formatted my HDD for the pc with the overheating issue. Now all of a sudden I'm running at 25c, with no signs of overheating or fluctuations or anything? I doubt reformatting fixed anything, but I've got my temps running low again so I'm happy.