My only problem now are the menus/UI , the Unreal Editor menus are very slow,it looks like the menus are lagging, it takes around 3-6 sec to move from one menu to another ?
Is impossible to work like that 
Any solutions?
(I am using Plasma with a high end pc, Nvidia 1080Ti and AMD Threadripper 1950x)
Never heard about an issue like this. Do you experience it with the UE4 editor only? Is it the menus exclusively or the overall input lag suffers as well.
I know that some Plasma TVs have a massive input lag making controls sluggish but 3000ms is unheard of…
This is happening only with Unreal Engine,
All other engines I have tested are working fine.
When I said Plasma = Plasma Desktop Environment (KDE)
Oh boy, the joke’s on me. Pff, thought the post processing was the culprit.
So your question really is: Why is the KDE framework making the UE4’s UI slow?
Somehow I feel you might have better luck finding answers in the plasma forums. A quick search brings artefacting and unresponsiveness into focus.
Not my area of expertise so I’m going to tap out. But good luck.
I have tested UE with MATE and it seems that is working fine so I guess it has something to do with KDE.
I am off to post this problem on KDE Bug Tracker List.
Thanks!