It's important to understand the surfaces you're mating. If for example, both are concave, the resulting gap will be detrimental to heat transfer. I've read in numerous forums where people purchase new heatsinks, and wonder why they're temps haven't dropped, and in some cases temps increased? This is due to the fact some Intel CPU Integrated Heat Spreaders, as well as custom heatsinks may have a slight concave or convex anomaly in their surface. In such circumstances it may have been the case your processor had a slight concave surface, while your stock heatsink had a slight convex protrusion. Ergo they mated well, albeit a relationship based on imperfection, it was none-the-less, functional. In purchasing your expensive perfectly flat, or slightly concave custom heatsink, that thermal transfer is now rendered moot. I tested the CF1's base plate surface, and was impressed to find near perfection.



Link: Madshrimps