Ever since I installed my MSI K8N-Neo4, the Northbridge has been the loudest fan in my system. The fan always spins at a very whiny 6800 rpm no matter what the case airflow was.
I decided to fix this problem by replacing my Northbridge fan with a passive heatsink that would fit with my Arctic Cooling VGA Silencer on my x800xl. After browsing the internet, I discovered that none of the (cheap) aftermarket sinks would work for my board because of video card clearance issues. As you can see from this picture, the video card would sit right on top of the Northbridge:
I stumbled across this thread and decided I would model my Northbridge cooler after ArcticOC’s cooler.
I looked through my old computer junk and found a heatsink I could mod to fit my motherboard. The heatsink is about 70mm x 70mm and has three rows of fins, as shown after I used a saw to cut the fins to fit:
The hard part was now to find a way to mount this on my motherboard. Because of electronic parts around the Northbridge, I had to mill out part of the bottom of the sink to make it fit – the area in red was milled down:
The two holes you see on the sink are going to be used to attach the heatsink to the motherboard. The top left hole is about a ¼ inch deep and threaded. The bottom right hole goes all the way through to the other side and is oblong so it can be easily mounted. Before mounting the heatsink, I lapped the area of contact:
The finished heatsink before mounting looked like this:
To mount the heatsink on the board, I used the screws from my Danger Den waterblock; these are two threaded rods with washers, bolts, and two springs for tension:
As a side note, you should be careful when mounting a sink like this because too much tension on one side and not enough on the other might cause the sink to chip your Northbridge! The final product, in all its glory:
My temps are excellent – under full load with my Athlon 3000 @ 290 x 9, it stays around 41 ºC. This mod worked very well and cost me a total of $0 because I had the parts laying around. If you have any questions, please email me.