Optimising Settings for SilhouetteFX - Roto for 5K Footage


Hi team,

I’m cleaning up and comping a few shots for a short film.
The shots have been given to me as 16bit EXR at 5K res - 5760 x 4320, I believe it was shot on a RED Scarlet

This particular shot has 282 frames - 23.1GB

My PC has 16GB RAM, i7, reading off SSD

Nuke loads and caches the sequence without too much lag, however I’m trying to get into using SilhouetteFX

I’ve changed preferences to use more RAM etc however it still runs way too slow - near unresponsive

Is this a case of 5K footage being too much for my PC or can I change some other settings I don’t know about?
Could anyone point me in the right direction?