HD Tach showing crazy graph?

[supaidaaman]

Ive got the WD3200KS 320gig drive and i ran HD tach, but i compared it to the anand tech review and my graph dips and dives all over the place instead of of a smooth line.

(here is the anand tech review. My drive is on the top graph)
http://www.anandtech.com/storage/showdoc.aspx?i=2803&p=5

(here is mine)

http://img216.imageshack.us/img216/666/wdhdpa5.jpg

it looks even worse when i run the shorter test...whats the deal?

 

[Rubycon]

That's typical if another process requests commands while the benchmark is running.

 

[Zepper]

Make sure you have file indexing disabled (all the time, not just for testing - it's useless and causes incessant drive accesses) and anything else that migh request drive services during the test or run the test under Safe Mode - SM should have no drive accesses except from the program you are running at the time.

.bh.