Laptop Hard drive RPM article
 

The reason for this article is to dispell the numerous rumors
surrounding hard drive RPM. Many people claim that the 7200rpm drives
are incredibly hot, and drain large amounts of power. They also claim
that a 7200rpm is MUCH faster than its 5400rpm and 4200rpm counterparts.
We try to find the truth regarding these rumors, and put numbers to the
claims.

http://www.laptoplogic.com/resources/guides/35/1/1/