yup, the MCX-4000, and if you want supreme performance, go with:
a delta screamer at 80CFM (and 52 dBA)
a thermaltake smart fan 2 at 75CFM but with a variable speed controller, 48 dBA max
a vantec tornado at 84 CFM and 55dBA
otherwise even a really quiet fan will do well with this heatsink
<A HREF="http://www.tweaktown.com/document.php?dType=guide&dId=120&dPage=1" target="_new">WinXP tweak guide</A>
<A HREF="http://www.tweaktown.com/document.php?dType=guide&dId=145&dPage=1" target="_new">WinXP tweak guide 2</A>