Scratch disk is larger than expected (Photoshop CS)
When you open a file in Adobe Photoshop, the Scratch Sizes indicator in the status bar at the bottom of the Photoshop document window displays a large amount of scratch disk space, regardless of the size of the file.
The scratch disk size may be significantly larger than in previous versions of Photoshop.
Solution: Install the Adjusted Refresh plug-in.
You can download the Adjusted Refresh plug-in from the Adobe website at www.adobe.com/support/downloads.
Note: The Adjusted Refresh plug-in may reduce the performance of Photoshop if you have more than 1 GB of RAM or use multiple processors.
When Photoshop CS starts, it allocates a larger amount of scratch disk space than previous versions of Photoshop. (The amount of scratch disk Photoshop allocates is based on the amount of RAM on the computer and the percentage of RAM set in the Photoshop Memory preferences.)
The Adjusted Refresh plug-in reduces the initial scratch disk usage when you start Photoshop, and reduces the size of the Photoshop image tiles. The smaller tiles allow the display to redraw in smaller pieces, reducing the time needed to preview some filter updates.