Ok... why in hell are you guys having so much problem with heat. I have an 120GB WD 7200rpm and don't have any problem at all. This drive have been on for 24hrs!!... So here is what I think is going on.
1. If you are placing your hand on the disk drive, it WILL heat up is a HD it suppose to.
2. Before releasing the HD the manufacturer put the HD to a series of test that involve heating and cooling the HD to insane temperatures. With this information they release a Temp. # which the HD can withstand without failing on information transfer. look for the drive datasheet on the manufacturer web page. here an example:
Ambient Temperature 5 to 55 degrees celcius (approx 131deg F). Is your drive up to 131 degrees??? (that's very hot).
3. Is strange to me that a new drive make that much noise. I can't even hear mine. return it! and get another one.
4. a 7200 rpm can run cooler than a 5200... there is no relation on this it depends on the drive!!!!!
5. Please don't place your hand on the back fan and say OHHH is hot!!. If you look inside you will se that the main function of the fan is to extract the hot air from the CPU heat sink. Did you place the hand before the HD exchange??? so how do you know it wasn't running that hot before!!!