Surface Mapped Athlon - Is Lapping Required?

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Now tell me, what do you see in the blob of thermal goo? A tree? A forest? A problem?

When we got our Athlon 550Mhz, the first thing we did was to rip off the heatsink and take a look under the hood. Right off the bat we noticed a few checks against good processor-to-heatsink thermal transfer. Not good. Ultimately four points for improvement became obvious as we looked closer.  Unflat processor heatspreader plate Surplus amount of thermal goo Raised heatsink edges interfere with proper contact Stepped heatsink design limits useful surface area for heat transfer   This image map illustrates problems surrounding flatness with the mounting plate...

Surface Flatness of Processor Plate :

Considering that the aluminum plate resting overtop the CPU die and L2 cache is the main place most of us will attach a heatsink - regardless of whether or not the Athlon has been cracked open to attach a GFD device - we decided to take a very close look at it. This plate has been termed the 'processor heatspreader', and is the main interface for many types of Athlon heatsinks. With that in mind, the importance of this plate in transferring as much of the heat generated by the CPU as possible cannot be under emphasized - especially for the overclocker.

Likewise if liquid cooling is being used (such as the MC2000 cold plate, or a Senfu variation) the cold plate should make perfect contact with the entire aluminum plate. Poor contact simply means the investment in the cooling device is being wasted - a bit anyway.

With the goo wiped off we just looked at the plate first of all. Visually it appeared to be very flat, with a smooth surface, but what the eyes couldn't tell us the micrometer would...