'With the 8.0.2 update After Effects introduced 2 very important but not very well publicized or easy to modify preferences that are crucial to proper throttling of AE, so I updated Throttle to include these prefs to make them easy to access and modify. ...[the first is] important on multi-core machines that don’t have at least 2gb of ram per core.
... The second pref is the ability to let After Effects continue rendering the Comp frame while you switch away to another application. They call this “Allow Idle Rendering”. Both of these prefs are only accessible by manually opening the AE prefs file in a text editor and knowing how to look and change the pref. Throttle makes this easily accessible from within AE.'
Read more and download at AE Scripts.