Laggy UE 4.26 UI in Empty Project

Community Community & Industry Discussion
1

Nvidia 1080 GTX
Ryzen 5600
16GB RAM
Windows 10

Open a project like 3rd Person Example.
Clicking in the 3D viewport = great 120fps performance.
Clicking in the Content Browser and moving the mouse = 20 or lower fps.
Clicking in the World Outliner gives similar results but it fluctuates more.

I’ve spent many hours trying to figure this out. I’ve tried searching everywhere online and most posts blame Nvidia GeForce Experience Share Overlay and/or G-Sync. I’ve disabled both and sometimes it works sometimes it doesn’t so I’m not sure if it’s the root cause. I’ve tried killing all kinds of background apps like discord, hardware monitoring apps, backup apps, work apps, etc.

Any help?

2

Ifound this post just now that saysto add -DX12 as a commandline to a desktop shortcut (no way to launch it from the epic games launcher, I find that so strange)
That commandline gives me great improvements. The editor is 120fps and when I mouse over the content browser, world outliner, or Details panel for actors - it now “only” drops to 70fps.

But that’s still kind of bizarre to me. Why does the Editor lose ~50FPS of performance for mouse movement? I presume it’s some kind of event handling in the editor itself for mouse over???