We'll need to know about the nature of this particular comp.
The reason: there are certain effects and techniques that DO NOT use multiprocessing, even if you chose to use it.
Also: how do you have the AE Cache configured? Are you using the SSD for it? You should.
Finally, I don't know if application files are the most efficient use of the SSD; as you're probably aware, SSD's may be fast, but they're pricey and low capacity compared to HD's. You may want to consider the normal HD for such things.
The Disk Cache is using the HDD (I assumed the cache should be on a separate drive from the main app...which is on the SSD).
Some details on this comp:
- Uses Element 3D on a few layers
- Has a few Expressions for controlling camera movements and layer positions based on keyed elements (pulled from audio)
That's about it. I didn't have any issues like this when using my iMac for this exact project. The only difference would have been the CPU and RAM allocations, but Multipleprocessing was turned on for this when on my iMac. That's what makes me think there's something odd going on with some of my RAM/CPU settings...just not sure what.
You are reserving far too little RAM for other software.
(Also, I recommend going through all of these materials: http://forums.adobe.com/thread/543440 )
Regarding the SSD: Putting your application files on it means that applications load/boot faster. This is fine, but that benefit is just when you first start the application. If you put your cache files on it, then you get the benefit every time that something is read from or written to the cache---i.e., many times per second, for the entire time that you're working. Put your cache files on your SSD. BTW, there's no reason to not put your application files and caches on the same SSD. The reason that you split things across multiple disks is to prevent simultaneous reads and writes to and from a slow disk; the program loading from disk happens at a different time than reading and writing cache files, so there is no potential for conflict and slowdown.