I recommend you get a custom built on from somewhere like extremeoverclocking.com.
The prometia mach 2 and the vapochill.......they dont cut it for quad cores. I was using the mach 2 and i overclocked this cpu up to 4.7, had the voltage up to 1.6. Within 5 minutes of doing a 100% load test on all 4 cores, the cooler heated up to 0* and shut down.
Get a custom one that is specced for the wattage of a quad core. Instead of getting on that you can brag about and say wooooo yeaa this baby hit -80*C..... get one that can handle a higher heatload and stay a little warmer around -50...
Think of it like this... yea a motorcycle is friggin fast as ****.... but try to get it to tow a boat.
Also the custom made ones wont hook into the mobo power button. Overclocking on a stock on SUCK!!!!!ok. you hit the power button, phase change unit cools down for 1 minute, then boots the machine up.. OOPS i pushed the cpu to hard and it is unstable, time for a cold boot. Shut machine down. Push power button....aww man, there is a 2 minute cooldown timer. wait 2 minutes, push button... wait a minute for it to cool down, power up..
When doing lots of ocing, it gets old.
I still have my custom made unit up in the attic.. I just have kids who always mess with my pc, and i dont want them being around that unit,, never know. And no i am not selling mine lol, i might decide to use it again one day. I am also not using water cooling anymore for the same reason..kids. Air cooling is just so easy lol