W500 disk speed: primary versus ultrabay.

[voxano]

Hi.

I have two identical 7200 RPM 500GB hitachi drives installed in my W500 [].
I get about 60-70 MB/sec for write and around 80 MB for read for the primary drive
and the solid 100 MB/sec for read and write for ultrabay drive.

Anybody knows why the primary drive runs slower?

Thanks.

[richk]

I am throwing out my best guess, based on no real knowledge, but I would expect that the disk caching algorithm would be more conservative on the boot drive, especially write caching.

[tpribors]

Actually the opposite. Removables tend to have write cache disabled.

[richk]

This is not considered a removable. Those don't cache writes because the power can be cut or the device unplugged suddenly. This is on the same SATA controller as the primary drive. To stop the ultrabay drive you go through an orderly process.

[tpribors]

The internal drive almost always has write cache enabled. You can disable it in the device manager but it is not typical. The bay drive has an option to optimize for performance (write cache enabled) or quick removal (write cache disabled). The default is WCE.

This is for my T60p with Windows 7. My recollection is the policy is the same for XP.

You can find this policy by going to the device manager, selecting the unit in the "Disk Drives" list of the device manager, and it is in the "Policies" tab for the device.

This policy is the same for every mobile system I am aware of.