<< I have an XP 1800+ OCed to 1.6 and it is running 44C under full load. I am using a thermalright sk-6 with 80mm panaflo.
You aren't including variables, you might have a different motherboard and your room might be cooler. 63ºC is a little high, but you can't use your 44ºC as a standard for all Athlon XP 1800s to be at. Asus motherboards tend to run Athlon XPs a little higher in voltage for stability, so the same Athlon XP you have might run warmer on that motherboard.
I think that he should make sure he uses Arctic Silver II and applied the thermal grease correctly. Also makes me wonder what type of case he has (a nice large one with good air flow or a smaller micro ATX case). >>
Yes I know this. I simply made the post to show what sort of temps I was getting under full load as some sort of point of reference. Even if more voltage is applied by Asus boards 63C idle is awfully hot. Would this increased voltage actually cause a processor to jump almost 20 degrees? I would predict that it wouldnt.
As everyone else has mentioned: make sure you have the heat sink applied properly and use some Artic Silver II or III, depending on what you can get your hands on.