Laptop Problems

i have recently come into possession of two laptops:
1. hp compaq presario 2500 (intel pentium 4 of unknown speed)
2. hp pavilion ze4300 (amd that runs at 1.66)
the question is can i replace my amd with the intel without my laptop melting from running too hot (the compaq has 3 fans and i only count 1-2 on the pavilion)?
alternatively, do you think it would be a better option to move everything (ram, better battery….ect) over to the compaq and use it instead. the only reason i didnt in the first place is due to a lot of cosmetic damage to the compaq’s top (cigarette burns, scratches, and the chrome ring has milky white blotches) so if it is so much of a better machine that i need to use it instead then i will but i don’t like looking like i pulled the laptop out of the garbage