sorry i'm not really familiar with the tech talk and im new on the forums.. im assuming hs/f means heatsink fan.. I dont know what you mean by stock.. i bought it at Compusa for like 10$. i have sealed it as much as i can.. it could be that the thing just doesnt fit right on the board. No I didn't use AS3.. I used regular thermal paste that came in a little packet with my old motherboard. Do i need AS3? Thanks for help