Client PC had some weird problems; could start sometimes, would shutdown, runs “slow” though usually fine. Used CPUID HWMonitor and the SiSoftware sandra to see what’s up and the CPU temperature was high (75 Deg C).

The SiSoftware sandra processor reports a CPU temperature which correlates with the HWMonitor TMPIN1.

Got this desktop back to base and popped the hood. Cleaned out the usual dust bunnies and then decided to check the CPU seating on the heatsink. This is a socket 478 on an ASRock motherboard so levered the heatsink retaining clip but the heatsink wouldn’t come out and seemed frozen in place. Used a bit of force and when I did get it out the CPU had been pulled out too from its ZIF – the CPU was firmly glued to the heatsink by dry white heatsink compound.

I thought of what to get that off – a scalpel would be too sharp and dangerous and not big enough and then I remembered my favourite kitchen knife – the slicing/ham/salmon knife. This is 30 cm long, straight edged (not serrated), thin, about 2cm wide and a rounded tip.

I put the knife edge up to where one edge of the CPU and heatsink touched and then applied pressure. The knife broke the glue bond and the CPU was loose. Used the knife to scrape the heatsink clean.

Re-assembly was easy, re-inserted the CPU back into its ZIF socket that it had been pulled from (obviously open the locking lever first !), added usual thin smear of new thermal grease to the heatsink and put it back though you may have to do this in conjunction with the heatsink retaining clips as the heatsink may need to go in at an angle so the clips can hook into the bracket.

Screwed back in fans and powered up. BIOS looked good with a starting reading from cold of 28 deg C then working its way up to 34 deg C. Then ran Windows and now HWMonitor and SiSoftware sandra say 38 deg C and this maxes out to 42 deg C.

That’s up to a 30 degree C drop. Now the system should stay stable.

ps: As a safety note clean the knife of any residue. White greases are ceramic based and one important ceramic is Beryllium oxide which is poisonous in a loose form. These are not used for thermal grease now but may have been used in the past and unless you installed the heatsink yourself (in this case I didn’t) you won’t know what the risk is.