D'oh!! It's the chipset fan which is causing all the noise.
(The fan towards the lower left in this image.)
The end of my video card is obstructing the fan, so I can't replace it with anything higher.
Not sure what to do - but man, this fan is LOUD. I blassted it with compressed air - and no change.
Are there bearings I can clean? Any way to lub it?
thanks again
(dead on RNT!)
here's a closeup:
