swapping internal hd question

If I were to swap out my internal 80gb hd on my G4 imac with a larger one (250, 320gb, etc) it wouldn't necessarily make my computer any faster, would it? Hard drive space has nothing to do with processor speed, correct?

Thanks!

it wont make it faster. if you hd is full its gonna make it slower though. if u want it to go faster get more ram

That's what I thought, but I wanted to ask just to be completely sure. If I'm willing to be brave enough to replace the HD myself, I might as well replace the 256mb ram stick with a 1gb. Thanks for the reply!