(help) Performance issues and heavy lags, Preview sometimes doen't work

• Open system preferences by pressing Alt + Ctrl + ;
• Go to Memory & Performance
• Assign an even multiple of 4 GB to other apps so you don't choke the system because 64-Bit systems tend to work better with pipelines that are 4, 8, 12, or more GB wide
• Assign at least 20% of your CPU power to other applications, so the system has a chance to run in the background while AE is chewing on pixels
• Move to Media and Disk Cache and reduce the size of the disk cache 40 or 60 GB so purging takes less time

Those suggestions should help. Get back to us if they do not.

You might also want to open the Creative Cloud app, go to the Apps section, click on the three dots to the right of the Open button for After Effects and try rolling back a build or a version because sometimes new builds have problems with certain system specifications. There are so many combinations of OS versions and driver builds that no software company can keep up with every possible scenario for every release of their product. 

Simply disregard the previous comment. Yes, AE is poorly multithreaded and barely uses GPU functions, but issues that severe cannot be blamed on just that. Per-core efficiency wouldn't be that poor and rendering a frame taking 15 seconds is just not right. However, nobody can operate in a vacuum so start by analysing the behavior by observing your task manager and resource monitor, update your graphics driver and possibly other drivers, check your cache settings, toggle multiframe rendering and performance settings, review your preview settings and hardware acceleration preferences. Screenshots of the relavant panels, the main workspace of your project, the performance monitoring and so on might get us on track as to what actually isn't working.

Mylenium

I'm sorry to say that no average modern PC, at budget or workstation level can handle AE well. It's not optimized for today's hardware, and the only upgrade you'll generally benefit from is longer previews, because more RAM means more frames, in a linear fashion. A faster CPU with more cores and more threads simply means you're doing more work on less of your CPU. You seem pretty competent in building a PC, so you should be aware that a fast single or dual core CPU just isn't generally available any more. Even workstations worth 5k-10k will see only negligible performance increases.

the issue is that your CPU is heavily multi-threaded. After Effects was made before the 2000's, and therefore before the popular advent of multithreading, GPU's, and multiple gigabytes of RAM. that's why these things do not help performance- AE just wasn't built to use them.

Most of AE these days is plugins, scripts, and effects, but most are still 8 bit or single core. That's why multi-frame rendering was a big deal- because the base program can't effectively split up one frame, you just send frames to random cores. The downside here, is that if two CPU's have the same number of transistors and speed, but different core counts, the one with fewer cores will render the most troublesome/immediate frame faster, but the one with more cores will finish more at about the same time. If you have 32 cores, you could end up rendering a whole second of footage, but be kept waiting on the next frame because it was rendered slower. TL;DR: more cores = spottier performance.

this is also why the GPU requirements are a measly 2-4gb of VRAM. it just doesn't use it, for the most part, and you can look around but the general consensus is that GPU assisted rendering increases instability in AE, and only speeds up a handful of effects. it's not gonnna use all of your GPU unless it's, like, a GTX 780.

As well, there's a reason After effects has 16gb of memory as a minimum, 32 suggested, and few editors would be caught dead without 64gb or more. https://community.adobe.com/t5/after-effects-discussions/memory-consumption/m-p/12946885#M200703 I go over it here, but TL;DR (again), AE has a naive implementation where it just slaps all the previews, uncompressed, in RAM, so mere seconds of footage take up several gigs of RAM. It's not a small amount of CPU used to pull and store frames into RAM either, when all the cores are rendering a different frame, and none are available to manage storage. AM5 and DDR5 might actually help slightly there.