foodfighter -- No question is "stupid." HSF's are spec'd to fit processors by socket. Either the XP-120, XP-90, XP-90C or the SI-120 are "universal" -- fitting either socket-478 and LGA775 Intel, or socket-939 (and earlier) with application of some minor hardware included in the box.
Here's where I'M WRINGING MY HANDS, PULLING MY HAIR and CALLING MYSELF "STUPID." Galvanized Yankee has described his pack-rat penchant for piling up cyber-junk, hoping for that day when it becomes useful. That was ME, also.
For years, I saved boxes of those plastic drive-rails and metal fittings with every hard-drive purchase, never finding an application for them. Now, I'm modding old cases, and the "kludgy-est" part of my work is in the fabrication of drive cages, choosing to simply pop-rivet them into the case, cannibalizing and cutting up discarded cages to make them fit together.
Last week, I took all those rails and fittings down to my friend Max at his hole-in-the-wall computer store -- cyber-junk which I trade for discarded ATX cases -- picking up this time an entire 90's-era ComPaq ProLiant Server with 486 mobo, EISA SCSI-2 controller, drives as thick as a loaf of bread and weighing each as much as a brick, with hot-swap fittings. Now -- for THAT case -- I shouldn't need to fabricate drive cages, but for others . . .
Now I see the innards of the Antec P180. I could DO that with plastic drive rails!! Darn it!!