I started UE 5.4 for the first time today by using a previous version of a project that I barely worked on and notice the editor started stuttering after the editor wasn’t focused on for some time.
So far this issue only occurs when using the Edge browser. I was able to replicate this by having the Edge browser in full screen in front of the engine. I waited 30 seconds, and when I swap to the engine, the engine would start to stutter and didn’t stop until I restarted the engine. It also happens if the browser is on the second monitor and focused on instead of the engine.
I tried it when the engine was minimized, no issue. I tried it with Blender and see if it causes an issue and nothing. I even tried on another browser, Firefox, and no problems. The issue apparently is Edge for some odd reason.
Decided to try and upgrade my project from 5.3 to 5.4 to make the best of the new tools, and this stutter was unbearable to work with.
I use another browser (Brave), but they share Cromium source code, and the stutter begins when I open/interact with the browser. It is a very strange issue how UE is affected by a lightweight program.
I have the same stutter but I narrowed it down to the Atmosphere tick box in the Show menu of the editor. If Atmosphere is unticked the scene runs smooth at 40fps. With Atmosphere ticked it alternates between 10 and 30 fps about twice a second.
EDIT: after further investigation it is the real time capture of the skylight in the sun and sky actor causing it. I have not a lot of memory though with 6 GB and a RTX 3060 laptop gpu