Yes, over kill!  This fan is capable of cooling the latest quadcore extreme, in full over-clocked state.  So my Pentium D (dual core) 2.8Ghz 800Mhz is no match for it (not that hot), but I'll be able to turn the fan speed down and run the fan very efficiently...and the cpu+fan only ran me about $135 with shipping.

It's a monster, and was difficult to instal...3 hours! (at a semi-leisurely pace)