Here's a story for you -- I took off the fan, just to see what would happen. I got to POST and went into BIOS, and the system froze. That is the first time I ever had my BIOS freeze up on me, so I didn't like it. But I tried it again, and went into Windows. These are the numbers that I have to compare:
-- W/ northbridge fan (sounded worn out) --
CPU - Idle: 44c, High: 52c
Chipset - Idle: 36c?, High: 36c
-- W/O northbridge fan (just heatsink) --
CPU: Idle: 41c, High: 45c
Chipset - Idle: ??c, High: 27c
Under high load, that is a 7c drop for CPU, and 9c drop for the chipset. WTF is that about?