Using a non round magnification ratio, causes frame lag and performance loss even with ram preview.
Using a non round (Fit) number slows AE down and causes lag in ram previewed frames.
The weird part is usually it gets worse when it gets replayed.

Example below here is 100% scale
https://i.gyazo.com/cc271c2d34db830a9002261e702c42e9.mp4
Example below here is set to fit and is 132% scale
https://i.gyazo.com/6bb216e313426c00f321a8bf0a8d9c79.mp4
As you can see the performance tanks when you have it set to fit. Even when its ram previewed.
Ventura 13.2
Using an M1 MAX 64gb of ram
Ae 23.2.1 build 3
