I have a slot 1 p3 500 Katami. I know these cpu's are not great overclockers. I have retail H/F and can only hit 575 stable and 600 is a crash in windows and the temp goes to 50 and at 575 temp reaches 48 load. I need the best slot 1 cooler becieds going extreme like water cooling and stuff but it would not be worth it on my Katami chip. I checked cpu data base and most people seem to hit around 650 with this chip I know it ant a big difference but it will help.