I recently heard that switching a small capacity laptop hard drive to a large capacity drive will slow it down.Im changing my 80GB 4200 RPM drive with a 320GB 5400 RPM drive.Is it true that the larger the drive the slower the laptop computer?
It's not true that a larger drive will slow the computer.
You could get a 320GB 7200RPM 2.5" HDD and get a nice bump up in performance of disk IO activities. It won't make the CPU or RAM faster, but you'll get faster boot times and faster program loading. You will loose some battery life with the faster HDD.