Slow Preview and Rendering in 26.2.1

I just switched over from Mac to a PC. The switch was quite a major upgrade from a 2017 iMac to a very high end PC.

Old 2017 iMac Specs: 

Processor: 4.2 ghz quad core intel core i7
Graphics: Radeon Pro 580 8Gb
Memory: 64Gb 2400mhz DDR4
Storage: 2tb SSD

New PC Specs: 

Operating System: Windows 11
CPU: AMD R9 9950X3D
Graphics: Nvidia RTX 5090 32GB
RAM: 64Gb DDR5 6000Mhz RGB
Hard Drive: 4tb NVMe Gen4
CPU Cooler: 360mm AIO
4 Fans
Motherboard: X870
Power Supply: 1200W Gold ATX 3.0

This is a brand new computer. Storage is completely free, hardware check shows all components running smoothly, and After Effects has zero additional plug ins installed as of now. It’s just the base download from the suite. As of this post, I downloaded After Effects on May 12, 2026. Current version is 26.2.1

When I open up an AE project and begin to do rotoscope edits, the entire system basically freezes and preview renders begin to play at a horrifically slow speed. I’ve tried clearing the cache on all forms, increasing the cache gb to 300, toggling all video rendering mercury modes, and looking everywhere for a solution.

I brought the same project back to my iMac 2017 and while slow, it’s playing better on there than my brand new PC. 

I tried doing a new AE project on my PC to see if my old AE files were having a hard time going from Mac to PC, but I still got the same issues. It’s good to also note that the footage I’m editing on is a compressed H.264 file with no added layers/FX on the timeline outside of a single rotoscope edit. With the specs I’m currently running, this shouldn’t be a difficult task at all. 

Is there a known issue with After Effects and NVidia RTX products? I’m quite reluctant to stick with this new PC if Adobe has no intention of optimizing it’s programs for PC products. Any help is appreciated.