Usually the spare drives we have lying around are old (relative) and therefore slower, which in turn slows the Paging to and from the drive, which in turn slows your system down.
The Paging File should be on the fastest drive, preferably in the middle of the drive if short of RAM, or on the ouside edge if plenty of RAM.
If it is truly a spare drive set the minimum for the Paging File at the same amount of RAM and set the maximum as big as the drive.
Bookmarks