Right,
Been testing with my xp-120 and *grumble* thermaltake 120mm tricolour fan.

With fan blowing down onto cpu I have 36-38 idle and 48 on northbridge according to the nice MBM settings posted on a thread here.

Now I simply switched my fan so it sucked, I then had 31-34 idle and 40-44 idle on northbridge!

Well, that was unexpected. I suppose it is helping to remove stale air around northbridge which lowers that temp which is nice!

Anyways give it a try please and post back!

Cheers!

Edit: I know its been written about a little here, but for the benefit of all might as well have a good thread on it!