Intel Core 2 Extreme QX6850 Performance Showcase
 

It took a small voltage bump to 1.45V in the BIOS to hit 3.73GHz. To achieve this, we raised the FSB to 466MHz and dropped the multiplier to X8. Once we hit our highest, stable clock speed, we were surprised how stable things were even with a relatively low cost standard HSF cooler. We used an Artic Cooling Freezer 7 cooler to achieve these results.

http://www.hothardware.com/articles/...xtreme_QX6850/