I have an extra 2nd cpu heatsink collecting dust. I've read about replacing the gpu for a cpu heatsink. Does it really work to replace the gpu heatsink for a 2nd gen cpu heatsink? I have a 256mb jasper 360. No rrod.

It does work. It's been keeping my falcon alive so far, but it's also in a Lian Li XB01 case. In the stock case you'll have to mod the fan shroud and move or lose the disc drive.