Setting image caching preferences (6.5)

As you work on a composition, After Effects temporarily stores rendered composition and source images in RAM for reuse, so that previewing and editing can occur more quickly. After Effects 6.5 caches rendered compositions at the layer level for faster previews; layers that have been modified are rendered during the preview, and unmodified layers are displayed from the cache.

After Effects 6.5 also includes a new preference to store rendered items to your hard drive when the RAM cache is full. When both the RAM cache and disk cache are full, frames are purged to make room for newly-rendered frames. Disk caching makes previews render faster by using cached layers that haven't been modified and rendering only modified layers.

Blue bars in the Timeline window mark frames that are cached to disk. Green bars mark frames that are cached to RAM.

Note: After Effects on Windows XP® can use more than 2GB RAM and up to 3GB of RAM for image caching. To use those amounts of memory for any other purpose in After Effects, you must configure Windows XP appropriately. (See the Microsoft Web site.)

To purge the RAM and disk caches:

With the Timeline window active, choose Edit > Purge > Image Caches.

Note: Disk cache is automatically purged when you quit After Effects.

To set memory and disk caching:

1. Choose Edit > Preferences > Memory & Cache (Windows) or After Effects > Preferences > Memory & Cache (Mac OS).
2. Type a value for Maximum Memory Usage to set the maximum amount of memory to use for any purpose. A value of 100% equals the total amount of physical RAM you have installed.
3. Type a value for Maximum RAM Cache Size to set the maximum amount of installed RAM to use for cached frames. The default value is 60%. Values over 90% aren't recommended.

Note: The number of frames that RAM Preview displays is also limited by this setting: Increase it to get longer RAM previews; decrease it if RAM previews are jerky or halting because of virtual memory paging activity.

4. Select Enable Disk Cache to move rendered frames from the RAM cache to your hard disk when the RAM cache is full.
5. In the Browse For Folder (Windows) or Choose Folder (Mac OS) dialog box, select a folder to contain your cache, and click OK (Windows) or Choose (Mac OS).

Note: For the best performance, select a folder that's on a different physical drive than your source footage. If possible, the folder should be on a separate drive controller. The disk cache folder can't be the hard drive's root folder.

6. In the Maximum Disk Cache Size box, enter the number of megabytes of hard drive space to use.