High CPU usage from EpicWebHelper on Linux UE 5.7.1

Summary

I’ve encountered a significant performance issue with UE 5.7.1 on Arch Linux that wasn’t present in 5.5 or 5.6.

  • Multiple EpicWebHelper processes consuming 30-40% CPU constantly
  • High CPU usage persists even when editor is minimized or not in focus
  • Affected processes: EpicWebHelper (storage.mojom.StorageService, renderer, gpu-process)
  • This behavior is specific to Linux; Windows version works fine

Please select what you are reporting on:

Creative

What Type of Bug are you experiencing?

Stability

Steps to Reproduce

  1. Install UE 5.7.1 on Arch Linux
  2. Open any project through Project Browser
  3. Monitor CPU usage with ‘top’ or ‘htop’
  4. Observe multiple EpicWebHelper processes with high CPU usage

Expected Result

Editor should have low/minimal CPU usage when idle (similar to UE 5.5/5.6 behavior).

Expected idle CPU usage: 5-10% maximum when editor window is open but inactive.

On Windows with UE 5.7.1 and on Linux with UE 5.5/5.6, the editor behaves
as expected with minimal background CPU usage.

Observed Result

Multiple EpicWebHelper processes consume 30-40% CPU constantly after opening a project.
The high CPU usage persists even when the editor is minimized or not in focus.

Specifically:

  • EpicWebHelper (storage.mojom.StorageService): ~37% CPU
  • EpicWebHelper (renderer/gpu-process): ~15-20% CPU each
  • Total idle CPU usage: 60-80% with editor doing nothing

This significantly impacts system performance and makes the editor unusable
for extended work sessions on Linux.

Platform(s)

Operating System: Arch Linux
KDE Plasma Version: 6.5.4
KDE Frameworks Version: 6.21.0
Qt Version: 6.10.1
Kernel Version: 6.18.3-zen1-1-zen (64-bit)
Graphics Platform: X11
Processors: 24 × AMD Ryzen 9 5900X 12-Core Processor
Memory: 128 ГиБ of RAM
Graphics Processor: NVIDIA GeForce RTX 3090

Workaround:
Adding these lines to Config/DefaultEngine.ini completely resolves the issue:

[/Script/WebBrowser.WebBrowserSettings]
bEnableWebBrowser=False

The workaround in DefaultEngine.ini only works when launching the project directly
(via .uproject file or with auto-open enabled).

When launching through the Project Browser/Launcher, the setting is ignored because
WebBrowser is initialized before project settings are loaded.

Has anyone else experienced this on Linux? I’m surprised I haven’t found other reports about this issue.

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