cpu an mounts to the heatsink. the heatsink mounts to the socket. If your looking for just the fam just measure it in mm and then google for a XXmm cpu fan. pay attention to the number of pins that are in the fan header you have (thats where the fan connects down onto the motherboard). Your current fan connector will have 2, 3, or 4 pin to mate with the connector on fan. While this is not overly important, its best to match the number of pins of the fan with the number of pins on the motherbd.