I'd set the timings to 4-4-4-15, and drop the speed so it appears as close as possible to 400MHz in CPUz.
This is your RAM yeah?:
http://www.overclockers.co.uk/showproduct.php?prodid=MY-072-OC&groupid=701&catid=8&subcat=813
Then push your FSB up a bit at a time, running Orthos for 30min each time.
This is your RAM yeah?:
http://www.overclockers.co.uk/showproduct.php?prodid=MY-072-OC&groupid=701&catid=8&subcat=813
Then push your FSB up a bit at a time, running Orthos for 30min each time.