AE unbearably slow on iMac Pro

[James Paulley]

I'm really struggling with AE being horrendously slow on a 10-core iMac Pro with 64GB RAM. I'm doing a bit of vector animation and as soon as the number of layers racks up a bit, AE is just so slow, both to render and preview, but also to use the interface and navigate the layers panel, etc. Can anyone help me think of any common do's and don'ts that might help me. I have turned off multiprocessing as that seemed to slow things down more. Beyond that, I haven't touched any settings. The only thing I was wondering was: I have quite a lot of script UI panels (screenshot attached), can they slow things down?

Running the latest AE and macOS.

[davidarbor]

ScriptUI Panels typically don't cause performance issues, although I've defintely seen my fair share of issues with CEP panels/extensions. An easy test for you is to switch to the Minimal workspace when this happens to see if performance improves. If it does, start closing your extra panels one-by-one until you find the culprit.

Multi-Frame Rendering should be giving you a major performance boost, not the other way around. I would turn it back on and try some other steps first. I've also seen other Mac users mention performance issues when MFR is enabled, so you can look around for other posts to see some suggestions. But again, there's no circumstance where MFR being turned off should be better than if it's turned on. I regularly see 2-4x performance improvements with it turned on.

Otherwise, without knowing how many layers you're talking about, what effects you may be using, whether Continuously Rasterize is turned on (if they're Illustrator vector layers and not native Shape Layers), whether you're previewing at Full resolution, what frame rate you're playing back in, and what dimensions your comp is, there's not enough information to give better recommendations.

[James Paulley]

Thanks! Good tip about switching to the minimal UI, I'll try that. I don't know what CEP panels are.

MFR was definitely not helping, it was definitely slower with it on. I've treid searching for other threads discussing this but no luck.

Does continually rasterise cause a big slow down with AI layers?

[davidarbor]

Sorry, CEP panels are extensions which are a more advanced type of panel. You can find these under Window > Extensions. They're basically scripts wrapped in a webpage, so some of the more attactive and interactive panels like Flow or the CC Libraries panel are extensions. It looks like all those panels in your stack are traditional ScriptUI panels.

CR can slow down AI layers since After Effects is doing exactly what it says, after each transform it's rasterizing the layer again, so there is extra processing, but it shouldn't wreak havoc on your system. Again, this is an easy test to quickly disable the switch to see if a single layer is causing the issue. I don't turn it on for a layer unless I need am scaling past 100% or doing a transform that looks better with it on.

As for MFR, do you find it's slowing down with just this project or just AI assets? Narrowing down where the issue is could help find performance bottlenecks and there could be a bug the AE team should know about. And  speaking of finding bottlenecks, are you familiar with the new-ish Composition Profiler? Check out this article to learn more about it. It can give you a snapshot in time about which layer, effect, or expression could be the cause of your performance issues. Make sure to read the article thoroughly to understand what's happening and how to interpret results, as you can see very different values on the same frame because AE will always try to reuse cached assets when available.