Help about cpu or pc fan speed

I am goigng to by a pc or cpu fan but i want to know how can i buy the fastest for the best cooling for e.x what are the requirements i have to look forward
(sorry for my english)
thanks a lot!!!
Answer #1
in general how old is you computer to determining if you need to buy a new computer or a cpu fan and whats you budget and whats your pc spec of right now
are you using it for basic or more like gaming
Answer #2
gaming