Inactive particle systems and performance starting PIE

When starting PIE in 4.14, my RAM usage climbs up from ~4.5 GB to 7.2 GB. Also it stutters for quite a while.

Some helpful folks pointed me to the profiler and instructed how to use it.

Initial pic (time from pressing play to being able to do anything: 2:45):


What is that even?

Ok, physics, particle system component… I only have one particle system with collision on, let’s try reducing it’s size while adding a dummy with the original size but no collision…

Time from pressing play to being able to do anything dropped to 0:47.

The particles start inactive, auto activate is off and are only toggled by a keypress in game. Why they should affect the time to start PIE so much?

Also I don’t think they affected 4.13 so much (I added the rain particles three days before moving to 4.14 and surely would have noticed if it took me 2 minutes to start PIE)

P.S. Anything else you see in there I could improve?