The best is to replace the thermal pads to avoid excessive overheating of the processor and graphic chip. You'll have peace of mind. You may use thermal pads or artic silver thermal paste available in any electronic shop. Also, just one advice, don't put too much pressure when screwing the two mounting bolts with springs on the heatsink. I use a 5/32" socket to do it. The mounting male part is soldered to the logic board and it's easy to desolder it if excessive force is applied when screwing. Other screws on the heatsink can be tightened without problem.