http://kadaitcha.cx/performance.htmlTweak #2: Disable Last Access Timestamp Whenever XP reads a file, it stamps the file with the date and time that you accessed it. This feature has its place but is not required for normal use unless you rely on the date of last access for backup purposes, which is a rare requirement for most backups. Putting a timestamp on a file that has just been read means that a write access has to be made to disk, so every time a read is executed, a corresponding write is also executed.
To disable the last access timestamp behaviour, start a command prompt, enter the following command then reboot;
FSUTIL behavior set disablelastaccess 1
Those of us who read and write Her Majesty's English need to take note of the American spelling of the BEHAVIOR parameter. To turn timestamps back on, repeat the command but replace 1 with 0;
FSUTIL behavior set disablelastaccess 0