Sometimes when the system is all bogged up, you need a shortcut to get you out of trouble and working as soon as possible again. Just make sure if you select ‘All’ you do not need to use the Undo feature. The ‘Snapshot’ and ‘Video Memory’ will only purge these items in the RAM, but the ‘Image Caches’ is the most important one to remember to clear out in order to release the maximum amount of RAM.
The ‘Undo’ selection will just clear all the Undos. This includes all of your Undos, so to clarify once you select ‘All’ your Undos will no longer be available. If you select ‘All’ everything in the list will be purged. You will notice that there are five options under the purge menu, All, Undo, Image Caches, Snapshot and Video Memory. After Effects will keep hogging your RAM until you purge your cache. The one thing you will notice when you go to open your editing program or another RAM hungry app is that your computer will start running very slow or it may lock up and crash, this is especially true if you are running a Windows machine. The green bar is displayed in your timeline any time you RAM preview your composition. After Effects is a very RAM hungry application that uses as much of your RAM as it can get to preview your footage and compositions when you press the ‘0’ on the numeric keypad.
