I recently got a new MacBook. How can I determine the hard drive speed (RPM)? I am using Mac OS X Version 10.5.8.
Apple Menu -> About This Mac -> More Info -> Hardware -> Serial-ATA
Depending on what type of hard drive you have, the RPMs may be listed as Rotational Rate. Not all drives report this however. If not, as that's the case, as jtb points out, you'll have to do a Google search on your hard drive model.
In my limited testing, Seagate and Hitachi drives seem to report the drive's RPM, but Western Digital drives do not.
EDIT: Update due to not all drives report RPM rates.