Faced fps drop problem in work project while was working with over 10 actor blueprints. They located in one folder and when this folder is open and mouse located over content browser window fps drops from 100-60 to 15-20.
Steps to reconstruct this effect in clear project(with starter pack):
- Create new folder
- Create at least 10 new actor blueprints in this folder, add some random static mesh (one will be enough). Duplicating blueprints might not work, only new blueprints.
- While folder with 10 actors open, move mouse over content browser, fps should drop.
Video with this effect - UE4Editor 2017 01 31 22 56 59 02 - YouTube . Actor blueprints are simply clear blueprints with only 1 static mesh.
Also I have noticed that after project reload folder with actors not affecting on fps. This effect returns if all blueprints were open at least once (no need to keep them open, simply open-close). Fps drop increases after each new blueprint was opened.
Folder full of static meshes also have same effect but less noticeable, from 120 to 60 fps.
4.13 version works fine, encountered such effect only in 4.14
My thoughts about this - blueprint thumbnails updating constantly after blueprint was opened at least once.