I originally posted this in the Media Encoder forum, but now I am convinced this is a After Effects 2015 problem, so I am reposting here.
After upgrading from CS6 to CC 2015, I found my render times became much longer. For example a project that would take 1 hour now takes 18 hours.
I have a Dell T7500 workstation with 32 GB of RAM and two Xeon processors that show up as 12 CPU in the resource monitor.
If I render a Premiere CS6 project that includes a After Affects CS6 comp, all 12 CPU are engaged and the CPU uses shows as 100% or even 103%.
Now, if I take the same project and update it for CC 2015, when I render through through AME, only one of 12 CPU are engaged, and the CPU usage hangs around 16% That is the first screenshot below. If I remove the AE comp from the project and render it in AME 2015, without the comp it engages all 12 CPU. The CPU usage is better, but doesn't go above 80%.
There was obviously some changes between AE CS6 and AE 2015 that changed the way rendering is done, and it is preventing it from using more than one CPU core. That is a major bug in my opinion.
My question is: is there something I can do in BIOS settings or in the AE settings to allow it to use all available CPU cores?
This screenshot shows the resource monitor while rendering a Premiere project with a AE comp included. Only one CPU is being used.
A render of the same project, only with AE comp removed, taking AE out of the equation. ALL 12 CPU are being used, but not fully.
You're right. There is a MASSIVE change in AE's renderer. It happened in CC 2015. The After Effects team is trying to do away with the buggy, old multiprocessing and replace it with something more efficient and faster. However, CC 2015 only contains part of the new architecture. They have SOME of it in place and it's great! You'll notice that the UI and renderer run on separate processing threads now. This means that interacting with AE is much faster in CC 2015. But they don't have the new renderer in place. See this: features not available in After Effects CC 2015 (13.7) (And they're still working through some bugs: known issues in After Effects CC 2015 )
The AE team has recommended working in CC 2015 and then opening that project file in CC 2014 to render it with multiprocessing. You don't have to do any clunky "save as" stuff either. It just opens! That's usually what I do and it works quite well.