I use a Scythe Mugen and my Q6600 overclocks easily 50%, don't use the Intel stock cooler and watch out with cooling pasta, use a half rice grain and a credit card to make a smooth surface on the cpu.
... nice ...
I get overheating with mine if I run the CPU at 3.6Ghz and push the cores to 100%, can´t see it being in the coolers though, ´cos ours´ are essentially the same thing and the Tuniq is / was one of the best ... its probably the massive difference in air temperature between Belgium and here then
To be honest ... my machine runs rock solid at 3Ghz, and I haven´t messed much with my overclocks since I set it up ...
Need my machine stable for work purposes - a couple of months back had a few days downtime after a bad experience experimenting with a crappy BIOS update ... wife nearly killed me ´cos she needed to work and I was madly trying to get it fixed! :doh: