I decided to make a new thread on the problem Mac Pro Northbridge overheating problems as I feel that the Northbridge issue along with over-hot RAM are two ('scuse the pun) burning issues for serious Mac Pro users. My previous post in this forum on this issue only skirted the edges of the problem.
I don't know about anyone else but I just cannot relax knowing how hot the Northbridge is allowed to get inside my new Mac Pro case amongst all those expensive hard drives and other vunerable bits.

As I type on my Sept 2007 Dual Quad 3Ghz Mac Pro, ATI X1900XT 9 gig RAM I have the following programs running . . Itunes, Safari, Firefox, PhotoShop CS2, Dreamweaver 8, Preview and iPhoto.

My Northbridge reads 46°C (114°F) in Hardware Monitor with an ambient room temperature of 22°C (71°F).
I put the Mac Pro through some heavy work with X-Plane, PhotoShop Gaussian blur, iDVD encoding video and a bunch of other stuff. The Northbridge never got over 58°C.
What temperature is your Northbridge showing? It may shock you.

I put together a page on how to reduce the Northbridge temperature. . .
http://www.hatsuon.net/macstuff/Northbridge/NorthbridgeTooHot.html


Here is one of the two changes I made, I replaced the Apple supplied Northbridge heatsink.


MIKX