What are your experiences with lapping?

[aPanzerIV]

I have read across the internet, and there is a bunch of mixed thoughts on weather or not lapping your cpu and heatsink is worth it.


I was wondering what the folks at CF think of this.

My experience tells me its really worth it. My dell E520 with E6600 at idle after 4 hours:



After running Prime95 for an hour:



I have lapped the cpu and stock aluminum heatsink with 1200 grit sandpaper. Applied AC5, other mods include 2x80mm fans in the back, and the 120mm fan in my psu. From 35c idle and 52c load to 24c idle and 39c load, that is quite an improvement.

 

[Celery]

Lapping the surfaces make them very flat that you'd almost need no thermal paste. That's what the thermal paste do, fill in the air gaps to allow heat transfer. Removing the air gaps means more metal contact.

 

[OhSnapWord]

In the old days, it wasn't unheard of for people to lap the heatspreader on the P4's.

 

[setishock]

On an Intel chip you'll notice the surface of the heat spreader is rough. This is done for a reason. The peaks and valleys present a larger surface area with out increasing the size of the enclosure over the chip. This allows lower performance heat sinks to do as good a job as a polished heat spreader and a higher performance heat sink.
And you will always have to use a thermal paste no matter how smooth the heat spreader and heat sink are polished. It is two different pieces of metal and a connecting agent will be required to increase the thermal transfer. Metal to metal with out a connecting agent is a fantasy.