Asked on 09/16/2008:

I recently installed the iStat widget on my Intel Mac Pro (2x2.66GHz dual core Intel Xeon with 3 GB RAM, running 10.4.11. It has the NVIDIA GeForce 7300 GT graphics card). I was surprised to find that the ™Northbridge temp™ normally is at 150°F which seems hot to me. The CPUs are at 80°F or so. This is when the ambient is about 65°F. Do you know what the optimal operating temp ranges should be for these?

Answer:The Northbridge chip is under the black heatsink in your PCI-e compartment of the Mac Pro. It is common for that chip to have readings up to 83°C or 182°F. Some people have taken to replacing the Northbridge heatsink in their Mac Pros to get things cooler, but I would not advise it unless you start to see temperatures above 170°F.