The freezer is a good shout although for a tenner more you can get the scythe mugen 5 rev b which is pretty close the big noctuas in terms of performance. That said I'm using a wraith prism on my 3600 and a 4.2 all core OC at 1.325v and I don't see above 67 in stress tests and 50-55 during gaming. Could probably pick one up for around a tenner as a lot of people buying the 8 and 12 cores go for an aftermarket so plenty of prisms floating about.
