After Effects doesn't use my RAM

[marietaf44351632]

I'm having major issues with After Effects' slow rendering (Quarter preview resolution) and exporing speeds when my system is fairly spec'd out: 

• RAM: 128GB T-Force DDR4 3200MHz
• CPU: AMD Desktop Ryzen 9 16 Core 5950X
• HDD: NVMe M.2 SSD Corsair MP400 4TB
• GPU: RTX 3070 GAMING PRO 8GB 
• OS: Windows 10 Pro 64-bit
• After Effects version: CC 2021

My project is in 3820x2160 but there are no render-intensive effects. Under Project Settings I've set 'Use: GPU Acceleration (CUDA)'. Under Preferences - Memory I've set 'RAM reserved for other applications' to only '12 GB'. Dispite everything, After Effects uses only 15% of RAM when playing a preview and 39% when exporting. (screenshots attached)

What do I need to do to force After Effects to utilise all the RAM that is available?

[David Arbor · Accepted solution]

After Effects will use all available RAM, so it would seem there's a bottlneck somewhere else. That being said, have you upgraded to AE 2022? This version introduces Multi-Frame Rendering along with a host of other amazing features to improve performance, but also tell you which layers and effects are causing bottlenecks. This upgrade alone should make your projects preview in the Comp panel, as well as render your final files, much, much faster. I typically see 2-4x speed increases when comparing comps with MFR disabled. You can read more about those features here: https://helpx.adobe.com/after-effects/using/whats-new.html 

You can install AE 2022 alongside AE 2021 (make sure to read the popup and uncheck the box to automatically uninstall previous versions if you want to keep 2021), but I've been using AE 2022 since it was available in the public beta and it's fantastic.

Also, regarding GPU-acceleration, AE still does most of its processing on the CPU, so while there are a number of GPU-accelerated effects and processes, enabling this option (which you should unless you're having other issues) will not make performance monumentally better like it will when enabling in Premiere. MFR in AE 2022, on the other hand, will result in significantly faster performance, especially on your 16-core machine.

[Mylenium · Accepted solution]

Sounds completely normal. AE will take what it wants and needs and quite generally there is no benefit to just using all RAM. That's an urban myth that just won't die, but dynamic memory allocation is pretty much the standard for any contemporary program, including AE. As David already suggested, if there are any performance issues that you think are not normal then they have otehr causes, but again, given your system specs it's very likely just normal that AE keeps chugging along at only a few cores and isn't using any fancy GPU acceleration. At the risk of making myself unpopular I can only direct you to the nundreds of "How to optimize performance" and similar threads here on this forum and elsewhere. AE's rendering piepleine is complex and full of quirks due to how old it is and managing it successfully to optimize render times is just as important as creating good-looking content.

Mylenium