For some reason, on quite a few of my projects, when I RAM preview my comps, I get the usual "Background process status - Loading projects..." message coming up in my INFO window, but usually the comp starts rendering the comp a few seconds after this message. However now I seems to get the "Background process status - Loading projects..." message for a good 3 - 5 minutes before processing of the RAM preview actually starts.
I've tried purging-all before doing a RAM preview, but this isn't helping. Has anyone else encountered this problem before and found a solution?
I have had this exact same problem, but only when working on complex projects with dozens or hundreds of assets. I assume it's because if I do a RAM preview with Multiprocessing on, AE has to load the AE render program ("aeselflink" in the Activity Monitor) plus a copy of my project 24 times; once for each processor core. I normally only use multiprocessing if I have a small project which is very processor intensive, eg. the comp I'm rendering is very high resolution, with extreme motion blur, depth of field, etc. but without dozens of assets which take time to save and load.
If you turn of multiprocessing in the preferences, AE will still use all your processors but won't have to do the background process palava.
I assume that if you turn up the RAM allocated to each processor, so AE uses fewer processors, then the problem will lessen, due to AE only having to load, say, 4 instances of your project.
Interestingly, I have another Mac Pro which, 90% of the time, is only used for 'watch folder' renders. I always have this set on multiprocessing, and it does not suffer from the background process delay when it starts a render - it just flies through it at an incredible pace. It keeps the 24 "aeselflink" render processes always loaded and ready to go. Which is nice.