Source: Photoshop Support Knowledgebase
Photoshop CS2 uses complex memory management procedures. On computers with 1 GB of RAM, or more, you can optimize Photoshop to take advantage of the quantity of RAM in your system to manage memory more efficiently.
About the Image Tile Size in Photoshop CS2
When Photoshop CS2 processes image data, it divides the image into sections called tiles. Each tile uses 68 KB of RAM.
You can activate the Bigger Tiles plug-in to increase the tile size to 132 KB. Activating the plug-in will reduce the overall amount of time Photoshop takes to process an image, especially on computers with more than 1 GB of RAM.
After you activate the Bigger Tiles plug-in, Photoshop will take longer to draw each tile and it may appear to draw images on screen slower, especially for large images or when applying some filters. However, the total time Photoshop needs to display the entire image will be less because it is drawing fewer tiles.
Activating the Photoshop CS2 Bigger Tiles plug-in
To enable the Bigger Tiles plug-in:
1. Close Photoshop CS2.
2. Locate the ~Bigger Tiles file inside the Photoshop CS2 plug-ins folder:
– Mac OS: Applications/Adobe Photoshop CS2/Plug-Ins/Adobe Photoshop Only/Extensions/Bigger Tiles
– Windows: Program Files\Adobe\Adobe Photoshop CS2\Plug-Ins\Adobe Photoshop Only\Extensions\Bigger Tiles
3. Rename the file, removing the tilde, ~ , from the file name.
4. Start Photoshop CS2.