AE Memory Settings

[Darby Edelen]

[Scott Bush] “Should I use less than all 8 cores for multiprocessing?”

Yes.

[Scott Bush] “Is there a cut and dry answer for this or do I just need to play around? “

A little bit of both. You don’t want to set your Maximum RAM Cache Size too high, as this can lead to memory fragmentation. That’s pretty cut and dry, but the specifics of your set up are up to you.

The Maximum RAM Cache Size determines the amount of RAM that is set aside for each rendering instance of AE. The maximum value is 3GB, but I don’t recommend using more than 2GB. So since you have 8 processing cores, each of which can run an instance of the AE renderer, and 16GB of RAM you could theoretically allocate 2GB of RAM to each core and use all 8 processors.

However, I would recommend limiting AE to using 6 of the processors. Allowing you to keep 2 cores and 4GB of RAM available for other processes. To limit the number of processes available for rendering to 6 you need to change the line "MaxNumberOfProcesses" = "0" in the file “Adobe After Effects 8.0 Prefs” (in System/Users/UserName/Library/Preferences/Adobe/After Effects/8.0/) to read "MaxNumberOfProcesses" = "6".

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[Scott Bush]

Excellent, many thanks for that very informative reply!

[Terry Coolidge]

A follow-up question about using all 8 processors of an 8-core machine during rendering. I typically don’t render in the background. I do previews here and there obviously, but usually when I’m ready to do a final render I queue things up, hit “render,” and walk away. I’m now thinking about buying a new dual quad-core (8-core) MacPro, and I picture myself letting the new machine render using all 8 processors and having my current PowerMac G5 as a machine to do other work on while rendering on the MacPro. Are there reasons why I shouldn’t do this? The idea of having 8 processors and only using 3/4 of them come render time seems strange to me. But maybe you’re suggesting only using 6 so that you don’t cripple the system from being able to perform other tasks while rendering. A clarification would be appreciated.

I’m vacillating between configuring a new MacPro with 8GB of RAM vs. 16GB of RAM. I keep seeing the word “theoretically” used when talking about allocating memory for a multiprocessor rendering, and I’m wondering if the upgrade from 8GB to 16GB is worth the cost. The extra 8GB of memory is only going to impact performance when launching a multiprocessor rendering, correct? I’m not going to see substantial benefits when I’m not rendering, am I? Is there some way of quantifying how 2GB of memory per processor would perform vs. only 1GB of memory per processor? Would double the memory significantly reduce render times over the course of an entire rendering, or does it mainly just help here and there during rendering as AE loads up the elements to render? I’m sure it depends on the project, but can you provide some sort of real-world example to help convey the benefits of extra RAM? 8GB (or 1GB per processor) seems like a reasonable amount, but if twice that is really going to make a huge difference, then I think I would want to consider that.

Thanks.