Severe lag in editor since UE5

General Feedback & Requests
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1

Hi

I stumbled on a weird issue which makes UE5 nearly unusable for me.

First: how to reproduce

  • Start UE5/5.1 (seems it’s in since 5.0)
  • Blank project (or any project for that matter)
  • Move the editor to the 2nd monitor (right hand) and maximize it there
  • try to use the File/Edit/Window/Tools/Build/etc menus
  • watch the lag

System:
Ryzen 5950X
64GB RAM
Radeon 6900XT graphics
runs from SSD (not that this should matter)
Drivers are all up to date
Monitors: dual 4K

As soon as I maximize any editor window on my 2nd screen the window menus are just unusable (hard lag, GPU spikes to 90-95% usage, system unresponsive) until I click somewhere else and the menu closes again.
This behavior is only present on my 2nd monitor with a maximized editor window, on my primary (which is my left) everything works fine.

PS: Checked with other screen setups (different resolutions, dpi, monitor layouts), result is always the same.

So, I have a request for those with dual monitor setup: Please try to reproduce this behavior and post something so I know I’m not the only one :slight_smile:

2

Are both monitors connected with display port?

3

Both Displayport, yes.

4

Do they both use the same refresh rate? I’ve read that there is a bug previous Radeon release notes that caused problems.

5

They are even the same model (Samsung LU28E590DS).
And the issue does not appear if the window is not maximized. So i can make the window 3840x2160 and the menus work. But as soon as i maximize it on my 2nd monitor menus are lagging like hell.

6

Have you tried turning on “Use borderless window” in project settings?
it should change the way it goes full screen to something more multi-monitor friendly

7

Just tried. Not working for me.

But that only should change the project. I’m talking about the editor itself.

8

Not the Solution:

In Project settings set the RHI to something other than default.
After editor restart you can change it back to default if you want.

Seems the problem only appears on systems which never did change this setting.

9

Seems this was not the solution…
Next day (fresh reboot) same problem :frowning:
Even changing the RHI back and forth doesn’t do anything now.

10

I am having this same problem and cannot find a fix either.

11

So I’m not alone.
Can I ask what gfx card you’re using?

12

Seems Radeon drivers 23.3.1 fixed it.
No more lags :grinning: