So this is kind of interesting. I did an uninstall and a fresh reinstall to fix a bug I had with not being able to associate my project files with the UE4 launcher (which fixed the issue). Now when I run my game in the editor, if I have input focus on it I don’t get any stuttering. I can however 100% repro the stuttering if I shift-f1 and mouse over various UI elements. For example, if I constantly mouse over items in the Scene Outliner or items in the content browser (the type of element doesn’t matter), then about every 5 seconds I get a full halt of everything in the UE4 editor for about a second. My game FPS goes from 120 to 0. The timing seems very consistent.
It’s not doing it when I mouse over entries in the Modes tab. It is doing it when I mouse over the toolbar (with the save/compile/etc buttons on it). If I just have a blueprint editor window up of my character, without moving the mouse at all and just sitting there, it’ll stutter. The tab doesn’t matter.