Problem with hard drive clicking
Many users have reported a problem with hard drive clicking, particularly with Hitachi's 5k80 series which currently ships with new T series Thinkpads. The clicks occur rapidly, and are quiet but noticeable. The clicks seem to happen when the drive is idle. Some users report that defragmenting their drive helps. Others recommend using Hitachi's power management utilities. Some other users report that nothing they try has solved the clicking problem. It is not known whether the problem is a sign of impending drive failure. Since the problem is so prevalent, if it turns out to coincide with high drive failure rates then Hitachi has another major drive quality problem to deal with, after the Deskstar 75GXP problem.
IBM's latest posted firmware, A5DA, does not appear to solve the problem.
External links
Thread on thinkpads.com Thread on notebookforums.com Thread on silentpcreview.com