You know what, my mistake,, I just replace the shot 4cm fan on the nortbridge about 30 minutes ago. It has the two mounting holes so I should be fine. I replaced it with a much heavier duty fan that came from a hard drive bay cooler.
(My CPU temps seem a few degrees cooler for some reason,,,, I also noticed that the CPU temps increased when the fan died,,, could the northbridge and the CPU temps be linked somehow?)
My temp now is 46 degrees full load, occasionally going back to 45, before i replaced the fan it was 48 to 49 degrees.