I just achieved a stable OC of my CPU running on Air Cooling at 3520mhz ( 1120mhz above stock ) with 1.36v and in quite good temps in comparison with most Air Cooled 6600s ive seen.
PS : I runned Orthos for 9 hours during the night but didnt snapshot it thus i did a new orthos for 10+ mins to provide a snapshot. Temps were even lower ( -1,2 degrees ) after 9 hours with Orthos..Weird.
C2D6600@ 3520MHZ IDLE
C2D6600@ 3520MHZ FULL LOAD / STRESS