One of the things that annoyed me when I had my original X41T was the disk clicking made by the hard drive. A post on the tabletpcbuzz might have discovered an explanation for this issue (snippet from the original post):
I read in a German Thinkpad-Forum that the X41 HD clicking could have this reason:
Some of the used Hitachi HDs have defective Caches. When no working cache is found the HD has always has to write directly. Therefore this clicking.
A German guy found this out with a tool: either with Sisoft Sandra or Hitachis Drive Fitness Test a defective cache (or non-existent cache) can be detected.
It seems that IBM and Hitachi already confirmed this defect. Both HD (40 and 60) shall have defective caches.
The entire thread is available at:
http://www.tabletpcbuzz.com/forum/topic.asp?TOPIC_ID=28538&whichpage=1
Everyone in the thread who has run the diagnostics reported having 0KB of Buffer (cache). Definitely worth keeping an eye on this thread.