Advanced RAM Tweaks

If you've already read this far into this topic, you're probably not against a little work under the hood to tune Photoshop efficiency. In that case, I have a few more tips for adjusting the balance between performance and RAM usage. The way you want to think about these tips is in terms of how much RAM you've got installed. If you have more than 2GB of RAM installed, you've got enough room to tune for maximum performance. If you have less than 2GB installed, you need to make compromises to avoid slowing down Photoshop. OK, here we go.

Bigger Tiles Plug-in

When you open an image, Photoshop breaks it up into tiles so that the tiles loaded into RAM are only those involving the part of the image you're working on. By default, Photoshop tiles are on the small side so that they're easier to load into available RAM. If you have more than 1GB of RAM, you can enable the Bigger Tiles plug-in. Bigger tiles mean fewer tiles, and moving fewer, bigger tiles is more efficient than moving more, smaller tiles, if you have enough RAM.

To load the Bigger Tiles plug-in:

1.	Go to the following folder, which is inside your Adobe Photoshop program folder: Adobe Photoshop CS2/Plug-Ins/Adobe Photoshop Only/Extensions/Bigger Tiles
2.	You'll find the Bigger Tiles plug-in with a tilde before the name (~Bigger Tiles.plugin). Delete the tilde.
3.	Restart Photoshop.

You can disable any plug-in by adding a tilde (~) before the name.

Cache Levels

Photoshop can use a portion of RAM to remember how an image looks at different zoom levels, so that you experience less of a delay each time you zoom in or out on a large layered file. Of course, there isn't enough RAM to cache every possible zoom level, so Photoshop is set to cache six zoom levels by default. If you work with large layered files and aren't short on RAM, you can set Photoshop to use up to eight cache levels. If you want to make more RAM available for other Photoshop operations or you work with small, flattened images, you can lower this value down to one cache level.

To change the number of cache levels:

1.	In Photoshop, open the Preferences dialog box.
2.	Choose Memory and Image Cache from the pop-up menu at the top of the dialog box.
3.	Adjust the value, click OK, and restart Photoshop.

Releasing RAM in a Hurry

Although Photoshop can normally avoid out-of-memory situations by using virtual memory, some filters and features need to do their work only in actual RAM. If the size of an image and the feature you're applying create more data than your computer's RAM can handle, it's possible to get an out-of-memory message. You can often save, exit and restart Photoshop, and try again.

In the worst case, you may see an alert that there isn't enough memory to save. This is bad because it means you can't exit Photoshop without losing unsaved changes. Luckily, Photoshop provides a way out that usually works: the commands on the Edit > Purge submenu (Undo, Clipboard, Histories, All). If you don't need your History palette history states, you might as well go straight to the Edit > Purge > All command and then try to save. Otherwise, you keep the most options open by choosing Edit > Purge > Clipboard and then try to save again; if that doesn't work, try the other commands. Note that even if you choose Edit > Purge > All, the History palette isn't fully purged until you manually delete the first history snapshot in the History palette.