I feel so bad right now. I have a 1.4ghz old laptop and bought a 1.8ghz cpu for upgrade (yeah i know...). So i opened the laptop up last night and then i realize the cpu is actually solder onto the motherboard well, so i was like, since i spent an hour opening it, maybe i should replace thermal grease just for the heck of it. So i clean everything with alcohol and applied some new AS5. When i try to put everything together, i realized one more thing. There is a gap between heat sink and the cpu. It was bridged by thermal grease before. After some googling, i realized a lot of laptops have a gap like that. My question is why is that gap even there? I am using AS5 to bridge the gap right now and its probably the worse thing to do.