Running LFS windows may give better results, I had not thought to try that. It's because Windows is handling the multi-tasking differently (or rather, LFS is waiting on a poll event which kicks Windows in. I will definately try that.
I can overclock to 10% without breaking my warranty, but I choose not too because 10% wont make the difference and i'd rather not blow the thing up.
You can run a P200MMX two days without a heatsink & fan before it explodes out of the socket (seriously, I worked for a PC manufacturer and one of the lads did it just to see what would happen, it crashed the first night, but didnt actually explode for 2 days). I've not tested a socket 939 chip in the same way, but i'm hazarding a guess here that it'll blow much faster. The integration scale isn't the same, the silicon is different, the processes are different, the power consumption is different, the heat is different, it's like comparing a Mini to a Ferrari... Take out the oil and rev it up and see which one blows first.