Ok here goes, how exactly do I know what size fan I have on my CPU? What measurements do I take? width of fan?, the length? the mobo form factor? The cpu in question is actually on a Snap Server 4000, and I think maybe its a PII or PIII.
Highth and Width of the fan in Milimeters is what designates the size. 60mm H x 60mm W x 25.4mm D, is the measurements of the Antec 60mm Smart Cpu fan, just as an comparison. So heat sinks require bigger fans such as CoolerMaster heatsinks can use, 70mm, 80mm. I dont think I have seen one with a 120mm fan yet, a little to big for this type of use. Dosnt have anything to do with the motherboard form factor.