Do MacBook Pros overheat due to extra paste?
A poster on Apple's support forums has apparently traced the overheating issue
plaguing some MacBook Pro owners to excessive thermal paste application. Indeed, Apple's service manuals reportedly advocate the use of an entire 0.2-0.3cc thermal compound syringe for each of the machine's CPU, GPU, and north bridge chips. This recommendation may lead to over-zealous
paste application, which appears to hurt thermal
A poster on the Something Awful forums put this theory to test by opening up his MacBook, cleaning off the existing compound with alcohol, and applying a more reasonable coat of third-party thermal paste. He claims the smaller coat of paste caused the machine's front and rear surface temperatures to go down from 54.0°C and 50.8°C—normal operating range, according to Apple—to a much cooler 39.9°C and 36.6°C, respectively. The new paste application supposedly makes the MacBook cool enough to comfortably run on the user's lap and has the side-effect of lowering fan noise, as well.
Thanks to Chryx for the link.