I recently OC'd my Q6600 processor to a modest 3.0GHz (up from 2.4) recently, and wanted to ease the slightly-worrying feeling of having a CPU reach temps of 80 degrees plus on a CPU benchmark (it peaked at 91!!).

I ordered and bought a Noctua NH-U12P Heatsink with a 120mm fan for around $100 delivered (I think it was through www.scorptec.com.au) and gave it a shot.

It was an easy install, with no major hiccups, and the thermal paste provided seemed to be spot on. The heatsink came with a bolt-through mounting kit to hold the 800 grams of cooling power which was simple to assemble. One difficulty was attaching the fan to the heatsink with the annoying clips, but 5 minutes and some mild cursing later and we were ready to go.

I booted up and ran the same CPU benchmark, and was unable to push the CPU temp higher than 51 degrees. Thats a saving of 40 degrees!! Super-silent, and certainly does what it says it will.

I highly recommend the Noctua NH-U12P!!
(sorry I couldn't upload a pic!!)