Determining the size of RAM & Scratch Disks in Photoshop
RAM is required by Photoshop store information while running the various commands. If not enough RAM, Photoshop will use the hard drive as a scratch disk. Space needed by the RAM for Photoshop scratch disk and each is 3-5 times the size of the file manipulated. For files that are too big, you can run a filter on separate channels so that only dealing with Photoshop files that only a third the size.
Selecting Scratch Disks
Use the fastest hard drives as the scratch disk, if available, select the type of hard drives with RAID. Select the disk that has a continuous space and do defragmenters periodically with the Windows Disk Defragmenter or from the Norton Speed Disk Utility. You can also partition the hard drive dedicated to the scratch disk. To change the scratch disk, select File> Preferences> Plug-ins & Scratch Disks.



