Auto save is able to activate during a cache preview. If caching for the preview processing takes up significant resources and the project is a large one, the PC is trying to do both at the same time and it can slow everything down to a snail's pace. You cant stop the auto save once it has started and accordingly the cache processing is then all but stalled. Auto save gets in the way of preview and can really slow you down. Surely there is a way to prevent auto save from activating during a preview????
There isn't. The AE team has been improving the auto-save lately. I've been in a conversation with them about this feature and have requested that behavior be changed. You can request it too: Feature Request/Bug Report Form
Thanks Szalam. I have submitted the request.
For anyone reading this at Adobe, it is a real problem and needs to be fixed! It it can slow down my work schedule considerably and really screw things up. Or I can turn off auto save and get really screwed up when AE crashes and I haven't saved my work for the last 2 hours. Really fundamental lack of functionality!