WHERE WERE YOU A YEAR AGO!?:)))))
I have suffered so much with this problem.
Partial Solution Found! (MSI Afterburner / RTSS is the culprit)
The main culprit for the severe stutter and FPS crash was MSI Afterburner, or more specifically, RivaTuner Statistics Server (RTSS).
The “Why”
The Unreal Engine 5 editor is a very complex application that uses DirectX 12 extensively for its UI. It seems RTSS (which handles the Afterburner OSD) tries to “hook into” or “inject” itself into every single UI element.
This was causing:
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The insane lag when just hovering over buttons.
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The catastrophic FPS crash when moving a window to a second monitor.
The Solution (If you need Afterburner for Undervolting)
This fix lets you keep MSI Afterburner running (which I need for my GPU undervolt), but stops RTSS from interfering with the editor:
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Open RivaTuner Statistics Server (RTSS). (It’s the app that runs alongside Afterburner, check your system tray).
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Click the green “Add” button and create a new profile for the UE5 editor. (Find your
...UE_5.x\Engine\Binaries\Win64\UE5Editor.exe). -
With the
UE5Editor.exeprofile selected, set “Application detection level” to “None”. -
(Optional) If that doesn’t work, you can try setting the “Global” profile’s “Application detection level” to “None” as well, but the specific profile for the editor should be enough.
The Results (Why it’s only 50% solved)
This fix made a night-and-day difference, but it’s not perfect.
What’s 100% FIXED:
- The severe FPS drop and stutter when just hovering the mouse over UI elements is COMPLETELY GONE. The editor UI is now perfectly smooth to interact with.
What’s PARTIALLY FIXED (The Remaining Problem):
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The dual-monitor problem is much, much better, but not fully resolved.
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Before: Moving a Blueprint window to my second monitor dropped my FPS from ~120 down to ~20 FPS.
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After: Now, doing the same thing drops my FPS from ~120 down to ~80 FPS.
This is a massive improvement, and the editor is usable again. However, an 80 FPS cap is still a significant performance hit, and I would like to recover those lost frames.
I already checked my NVIDIA settings, and G-Sync is fully disabled, so that is not the cause of the remaining 80 FPS drop. I am still investigating how to fix this final part of the problem.
BONUS TIP: I also recommend disabling “Hardware-accelerated GPU scheduling” (HAGS) in Windows Settings (under Display > Graphics > Default graphics settings), as this can also cause conflicts with professional DX12 applications and disabling it can gain back a few more frames.
Hope this helps anyone else pulling their hair out over the UI stutter! I’ll post another update if I find a fix for the remaining 120 → 80 FPS drop.
