Every day in our labs we see many different mistakes regarding cooler installation and use of thermal grease.
The most common is using too much thermal grease. Excess of thermal grease spoils the correct heat dissipation, besides the possibility of drop to the outside and putting the system in danger.
Processors that have exposed components, such as the Athlon XP, can be subject to short circuits if the thermal grease closes the contact of its bridges or of the exposed components, such as capacitors and resistors.
In the processor in Figure 42, besides the excess of thermal grease, someone stuck a warranty seal right on top of the processor rubber pads that support the cooler. The thickness of that seal increases the pressure on top of the processor, and this pressure can break it.

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Figure 42: Duron with too much thermal grease and seal covering the rubber pads.
Another very common mistake are the warranty seals placed on the contact part between the heatsink and the processor. Don’t accept processors with seals covering it. If you have a processor with a seal on its top, remove it right away.
The processor in Figure 43 is a poor 200 MHz Pentium MMX. Besides the seal covering practically the whole contact area between the processor and the heatsink, it was also using the cooler in Figure 7, that uses graphite as heat conductor.

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Figure 43: Seal covering practically all the processor.
Other problems that we frequently see are broken processors – mainly Athlon XP and Sempron socket 462 processors – due to mistakes during cooler installation (putting the cooler at the wrong position or using too much strength when fixing the cooler) and people that substitute the thermal grease to toothpaste, liquid silicone, olive oil, glue, etc. Believe us, it happens!

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Figure 44: Socket 462 cooler installed in the wrong position.

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Figure 45: Processor damaged due to bad cooler mounting.