it depend on your VID on your processor.my high VID 1.3000V Q6600 cant overclock anything over 3ghz with the Artic Cooling Freezer 7 Pro(lapped).bios 1.35v load 69C.but i have seem some overclock to 3.2 and 3.3ghz with low VID
If you have good back case fan the AC pro 7 is very good.
Don't know about Xigmatek, but mine AC keeps my e2160 @ 3.0 Vcore 1.36 in idle at 34oC load 45oC(58oC cores), and without back fan it goes way up to 63oC and 70oC on cores.
back fan and front fan is a must as its needed for the air flow inside the case.but the OP and me is OCing a quad core.so heat output will be much more higher if not twice!lol
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