Arctic Silver 5 attempt
I have the same problem/issue you all do with temperatures--mine run in the low-to-mid 50's (according to RM Clock (which I really love, both for this machine and others; it's great for under-volting)) and it runs it's fans far too often for my liking.
So, I decided I would take it apart and put Arctic Silver 5 compound on it, or at least see what's going on. I wanted to share what I did, so this is going to be a lengthy post.
What's going on is that there are two thermal pads that connect the northbridge and the CPU to the heatsink, and there is a heatpipe connecting the cpu to the fan.
But, it seems like kind of a dumb setup, imho: the heatpipe that connects the cpu to the fan area doesn't really have any other kind of fins or anything anywhere (next to the fan) for the air to move through to help cool it down... The cage around the fan also seems to be lacking any kind of fins as well. (but I didn't take it apart)
here's a couple pictures showing what I'm talking about:
from the side, you can see that there's only a thin sheet of metal next to the heat pipe. (click for a bigger image)
Here's a picture of the top of the heatsink, with it's heatpipe (the cpu is in the corner):
And the bottom:
The thermal pads are about 1mm thick, and the one over the heatsink is about 1.75cm squared, but the actual die of the core-duo is much much smaller: there is a very thin copper shim under the pad (maybe 1/10th of a mm?) that was pretty thoroughly stuck onto the die. I didn't pry it off, so I don't know how large the actual die is. The thermal pad over the northbridge was about 1.3cm square, and the northbridge die was just a bit smaller.. maybe 1.1cm? (didn't measure closely)
So, there we are: two thick thermal pads & a complete lack of fins to help cool down the heatpipe; no wonder these things get toasty!
I may see if I can get some thicker copper shims machined, but I'm not sure if the heat actually getting to the heat pipe would do much good!
What are other people's thoughts?