Thanks for your reaction Joe,
I use large PSD’s because I’m ‘flying’ past them with the camera, sometimes really close, so I need the high resolution.
Here is an example:
https://www.freakinframes.com/video/MBH_Leader_2011_DefSouns.mp4
You can see I sometimes have over 100 layers in a comp, not all of them are super big, but most of them are PSD files.
While working on the timing of things i switch off the lights, depth of field of the camera and put it to quarter resolution.
The output is HD (1080×1920).
I guess I just have to accept that it is slow if I want to keep transparancy.
Regards, Niels