This is just my 2 cents, but I would avoid messing with such a delicate component of my laptop if not strictly necessary. I would first try a software solution like OS optimization and registry tweaking followed by benchmarking (there are many utilities for that on Windows). You can also create BIOS profiles to experiment with etc. Of course removing dust/debris stuck in the air cooling system will also help. A further step could be a light/moderate undervolt+overclock, still being extremely careful and keeping in mind this procedure will definitely void your warranty, just like a fan replacement would. Obviously you'll want to monitor your laptop temperatures and go one little step at a time