Problems with drive speeds in Win 7

[dreadedpestilence]

OK, I have a bit of a strange problem and was hoping someone might have the answer.

When I run hdtune in win 7, drive speeds seem to dip dramatically (sometimes down to 2mbps), whilst when a hdd is run as a non-os drive the results are fine. I turned off Windows search indexing, but it made no difference. I've tried this with 2 different drives, to rule out a drive problem. I'm using the latest Intel storage drivers.

The system is as follows:

i7-2600k
MSI H61 E33 board
8GB RAM

HD204UI boot

HD204UI non-boot

HD502UI boot

HD502UI non-boot

 

[drescherjm]

This is expected, What you are seeing during the dips is that the OS is accessing the disk. In windows the OS periodically accesses the disk for many reasons.

 

[dreadedpestilence]

OK, win 7 seems to access the disk far more than xp, for exactly what reasons does it do that?.