I noticed successive animations caused increasing amounts of lag and CPU usage. For example, during Zahra's harem scene in the living room, it plays hz-9-anim --> hz-10-anim --> hz-11-anim and so on until you cum and it switches back to still renders and the lag is gone.
hz-9-anim played fine, but by the time it gets to 12 and 13, it's lagging like hell. I tried editing the script to play hz-12-anim instead of hz-9-anim for the first animation, and it didn't lag. So the videos themselves are not causing the issue. Could it be that the animations are still playing in the background when it moves on to the next video?
Here is the relevant part of the script, but other scenes that play multiple animations in a row seems to cause the issue.