Percentage of RAM used

Question

Hi all
I have been playing around with memory settings for AE CS5.5 and taking some advice from here:
blogs.adobe.com/toddkopriva/2010/10/please-try-recommended-memory-settings-for-after-effec ts-cs5-and-give-feedback.html
and here:
http://forums.adobe.com/thread/734343?start=0&tstart=0
With variety different compositions, and different memory settings I have noticed my 'RAM: % used of 24GB' in my Render Queue window (at the bottom of the window) is always pretty low. Anything between a few % and 25% ish.
Is this just showing me the RAM used for the foreground CPU and not the collective CPUs?
Any info is much appreciated.
Cheers
A

Answer 1

What happens with MP processing is that one CPU renders a frame and at the same time the other CPU's try and render other frames at the same time. You don't get multiple CPU's working on the same frame. AE doesn't work like that. Most MP aware software doesn't either. The standard multi threading usage is to divide up the tasks and send them to a CPU to complete. AE's 'task' is to render a frame. The MP processing in AE isn't smart enough yet to divide up a frame into pieces and send the pieces all to the renderer. I've been asking for line rendering for a long time. AE builds a whole frame at a time as a single process. That's why AE's MP rendering is a little wiggie. (wiggie is almost buggy)
I'm also saying is that if your project is MP compatible that each CPU can render a frame at a time and that more than one frame may be rendered simultaneously, but if there is anything in your project that is not MP aware each CPU will try and render, get confused because the something like a codec or an effect is not MP aware, and the system will hang until it gives up and tries to render with one CPU. When that frame is rendered AE will start over with the next frame try and send multiple frames to multiple CPU's and try to render multiple frames simultaneously, get confused, fail, and finally render a frame with 1 CPU and then start the process again. This is why throwing in an effect that is not MP aware for one shot that only lasts 10 frames in the middle of a comp would, without that effect, efficiently use MP rendering  will cause the render to hang up and dramatically increase render time or fail completely. That's why I seldom of ever have it turned on.