Disabling Hybrid Hard Disks in Windows 7

My Dell Latitude D830 shipped with a 120 GB “hybrid” hard disk, in my case a Seagate Momentus 5400 PSD. These disks integrated 256 MB of flash memory on them to help the OS spin down the drive and speed certain operations through the use of ReadyDrive on Vista and Windows 7. In practice, this setup works terribly. Disk I/O slows to a crawl as everything is funneled through the ReadyDrive cache, and everything on the machine suffers. For a guy like me that does a lot of photo editing on my laptop this has to end.

To disable the hybrid hard disk modes on Microsoft Windows Vista and Windows 7 do this:

  1. Start->Run, and run “gpedit.msc”
  2. Computer Configuration -> Administrative Templates -> System -> Disk NV Cache
  3. There are two options you can enable:
    1. “Turn Off Non Volatile Cache Feature” — this disables the NV cache completely, which will increase your boot & resume times, as well as disable the option to run completely out of the NV cache and spin down the drive.
    2. “Turn Off Solid State Mode” — this keeps Windows from storing frequently written data in the NV cache. In practice this ends up being file system metadata and the registry. You have to have “Turn Off Non Volatile Cache Feature” set to disabled to use this.

It seems to me that the NV cache is much slower than the drive itself, probably for a variety of reasons, and with 4 GB of RAM on my laptop the OS ends up caching the filesystem pretty well with the unused RAM. So I enabled (enabling these options causes these features to be disabled) both of them and restarted. Much better!

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