QUOTE(HrutkayMods @ Jun 12 2012, 11:53 PM)
I know that Micro$oft went back to the 1st gen GPU heatsink for the Jasper Kronos for some reason. I heard multiple rumors like the 2nd gen heatsink wasn't needed any more, it was a cost saving measurement, and the one that kinda freaks me out, but I don't really believe... It caused uneven cooling which resulted in the E74. I personally thought that the heat pipe worked quite well. Since I installed an 80mm case fan into my 512mb Jasper, I figure that if I up/downgraded to a 2nd gen GPU Heatsink I would get the most efficient cooling with the 80mm fan if it was blowing on the extended pipe heatsink... I have a ton of the old 2nd gens laying around but I'd like other people's opinions first before I do it. So what do you think?
Both of the first reasons are true. The Jasper GPU does not need the 2nd gen heatsink, and as an added benefit, it saves microsoft money. Jaspers being the most reliable 360s to date, I'd say you would be wasting your time replacing that heatsink, but it won't hurt anything so have at it. While you're at it, you can put a first gen CPU heatsink on there instead of the 2nd gen because the first gen has more efficient cooling (switched to 2nd gen when they reduced the power consumption of the CPU in falcon models because they didn't need as much cooling and aluminum is cheaper than copper).
So in summation, you'll get the best cooling from the same heatsinks that were shipped with Zephyr Xboxs.
CPU: 1st gen>2nd gen
GPU: 2nd gen>1st gen
EDIT: Also, adding extra fans will just mess with the airflow of the fans that are there. If you want better airflow, modify the stock fans to run at 12 volts (not that you even need to do this with a jasper either lol)