Loading large videos in After Effects takes ages the first time. Any way to improve it?
If performance is sluggish, I would make sure the videos are the same resolution and frame rate as the format you plan to deliver your final video in.
So if the videos you are trying to import are 4K, but you're working in HD in After Effects, I would transcode the videos down to HD.
Also use a non-GOP codec like ProRes instead of h264/mp4.  They perform better when editing, because the software doesn't have to &quot;look ahead&quot; across multiple frames in order to work out how to draw the current frame.