Just wondering when you installed your Silent drive did you remove the feet on the HD? I've notice alot of ppl have been installing these drives incorrectly and the plates aren't even touching the drive.
Honestly i wouldn't use a silentdrive on any newer 7200 HD, it shortens the life of your HD pretty significantly, even with active cooling over the heatplates, the heatplates might be cold but its gonna be alot hotter inside. With 80mm fan blowing over em its temp is fine on the outside that is, without it its some 30f over ambient which i don't feel safe at all, inside id expect it too be double that. And my HD ran ice cold without it(silentdrive) and its one of the earlier 7200 drives that aren't as powerful as todays and runs much cooler then any 7200 drive i've had my hands on. Of course we are going beyond the drives specifications, which is 5400 drive thats under 5 watts of dispating heat, not all 5400 drives fit that spec.