I recently got after effects, so I am far from an expert. It is acting really sluggish. When I try scrubbing the playhead, it has a frame rate of probably about 5 fps. When I try playing the movie, it plays about half of what it was set to, and when I do a RAM preview, the little green bar, never goes all the way across. It will take away from other parts it is rendering, or it will just play the first 5 seconds. It may just be my computer, but there has to be a way to be faster than that. Vegas plays just fine.
Oh yeah, I almost forgot, it is also taking 115MB of my memory and the CPU usage goes way up.