I installed the latest Windows version of UE5.4.0. Whether it’s creating a new blank project or upgrading past projects from 5.3.2 to 5.4.0, I encounter the same problem - after the project is opened, running for almost less than 5 minutes, the operation becomes extremely laggy. This lag is not due to insufficient frame rates, but feels like something is causing a sluggish response after consuming a large amount of memory. Lag occurs in the blueprint editing page, in the viewport, and in the bridge page. It lags no matter where in the UE editor. However, at the same time, there is no lag when switching to the desktop or other applications. Memory usage appears normal. Can someone help me figure out what’s going on and how to solve this problem? Thank you.
Besides,I’m working on the 64bit Windows 11 platform.
Steps to Reproduce
Create a new basic Level
open a project with UE5.4.0
add DirectionalLight to the viewport
add Skylight to the viewport
add SkyAtmosphere to the viewport
add ExponentialHeightFog to the viewport
add VolumetricCloud to the viewport
open the Level Blueprint
add some nodes to the Blueprint
Expected Result
Extremely laggy after around 5 minutes using UE5.4.0
I have a similar issue, but the lag is constant from the start when running around in the level.
I have some code running relatively intensive calculations on background threads before returning the results and doing some work on the game thread.
But the weird thing is that if I open a window (plugins settings, project settings or even just a prompt that I need to restart the project for some changes to take effect) and keep it visible the lag goes away completely.
The bottleneck according to the performance graph when lagging seems to be: “Draw”.
Any ideas to what may be causing this?
Experiencing the same issue, although is not a lag as in FPS drop but it’s a freeze, it runs smoothly for 1 sec and then it freezes for 1 sec, you can see this in the FPS stats bar.
The lag occurs everywhere and from the beginning of loading or creating a project: In the render window, scrolling the Details and Outliner, scrolling ‘Project Settings’ and ‘Plugins’. I did not opened any blueprints or materials to check if there is lag there too, but even if there isn’t, the program in its current state is not suitable for working.
This happens even if I make a new project directly from a UE 5.4 templates.
I created a new ‘Basic Level’ and disabled Lumen, Virtual Shadows, Directx, basically I disabled everything and the issue remains.
I tried verifying files > uninstalling - reinstalling > change UE drive location > change priority in task bar > add exception to windows security
But nothing, the issue is persistence.
In UE 5.3.2 while loading my most heavy level with complex landscape shaders and functions running, on ‘Epic’ scalability I’ve the lowest 67 FPS locked, so the issue is not my PC can’t handle it.
64 bit Windows 11 - AMD 16 core Ryzen 7 3.8GHz - RTX 3060 - 32 RAM - SSD
I checked the ‘output log’ after loading a basic project created from UE 5.4 templates and got this, although I’m not a tech wizard to understand what it’s saying:
Summary
LogStudioTelemetry: Started StudioTelemetry Session
LogWindows: Failed to load ‘WinPixGpuCapturer.dll’ (GetLastError=126)
LogWindows: File ‘WinPixGpuCapturer.dll’ does not exist
PixWinPlugin: PIX capture plugin failed to initialize! Check that the process is launched from PIX.
LogConfig: Applying CVar settings from Section [/Script/RenderDocPlugin.RenderDocPluginSettings] File [Engine]
RenderDocPlugin: Display: RenderDoc plugin will not be loaded. Use ‘-AttachRenderDoc’ on the cmd line or enable ‘renderdoc.AutoAttach’ in the plugin settings.
LogSlate: SlateFontServices - WITH_FREETYPE: 1, WITH_HARFBUZZ: 1
LogStreaming: Warning: Failed to read file ‘…/…/…/Engine/Plugins/Developer/PlasticSourceControl/Resources/Icon128.png’ error.
LogSlate: Could not find file for Slate resource: …/…/…/Engine/Plugins/Developer/PlasticSourceControl/Resources/Icon128.png
LogStreaming: Warning: Failed to read file ‘…/…/…/Engine/Platforms/VisionOS/Content/Editor/Slate/Launcher/Platform_VisionOS_24x.png’ error.
LogSlate: Could not find file for Slate resource: …/…/…/Engine/Platforms/VisionOS/Content/Editor/Slate/Launcher/Platform_VisionOS_24x.png
LogStreaming: Warning: Failed to read file ‘…/…/…/Engine/Platforms/VisionOS/Content/Editor/Slate/Launcher/Platform_VisionOS_128x.png’ error.
LogSlate: Could not find file for Slate resource: …/…/…/Engine/Platforms/VisionOS/Content/Editor/Slate/Launcher/Platform_VisionOS_128x.png
LogUnrealEdMisc: Total Editor Startup Time, took 13.937
LogSlate: The tab “TopLeftModeTab” attempted to spawn in layout ‘LevelEditor_Layout_v1.8’ but failed for some reason. It will not be displayed.
LogSlate: The tab “TopLeftModeTab” attempted to spawn in layout ‘LevelEditor_Layout_v1.8’ but failed for some reason. It will not be displayed.
LogSlate: The tab “TopLeftModeTab” attempted to spawn in layout ‘LevelEditor_Layout_v1.8’ but failed for some reason. It will not be displayed.
LogSlate: The tab “TopLeftModeTab” attempted to spawn in layout ‘LevelEditor_Layout_v1.8’ but failed for some reason. It will not be displayed.
LogSlate: The tab “TopLeftModeTab” attempted to spawn in layout ‘LevelEditor_Layout_v1.8’ but failed for some reason. It will not be displayed.
Same here. 5.3.2 was perfectly smooth, but 5.4 constantly seems to be chugging and just freezes (in blank projects) for 2-6 seconds every 5 minutes. Spent hours trying to improve it, failed. Will wait until someone addresses this to use 5.4 again.
Does the weird “work around” of keeping another unreal window (eg. project settings) open work for anyone else?
(it completely removes the lag for me.)
I have the same issue. Every project that ran at 13-15ms in 5.1 is extremely laggy in 5.4. No matter what I do, I can’t get it to match the frame rate of 5.1, it’s usually 50%-80% slower in fact. I’m also getting the same issue with what appears to be a memory leak or something where it gets extremely stuttery after a few minutes, and a minimum of a drop of 30 fps in every single project I try compared to 5.1. It’s running off an new NVMe drive on Windows 10, 64GB RAM, Ryzen 5900X 12-core 3.7MHz and a 3060ti card, and is completely unusable in it’s current state.
I have tried using an old editor lag fix by disabling UDP and TCP Messaging in the Plugins tab. Additionally, I have disabled the Studio Telemetry Plugin for now. As of now, my Unreal Engine 5.4 is running very smoothly, but it may still need further testing to ensure the issue is fully resolved. If your project relies on TCP or UDP messaging, this fix may not be suitable for you. Please let me know if disabling any or all of these mentioned plugins also works for you
Okay, I tried something else; instead of storing my projects on my HDD, I moved them to the m.2 C: drive where I keep the engines installed. This seems to have fixed my 5.4 lag, but it’s odd because I’ve always had my projects on the HDD.
I think 5.4 may require quicker disks.
Among all the voodoo and black magic I tried, there was one that gave some mixed up results:
I turned off internet connection > lag was there
Restarted PC > turn off Internet > lag disappeared > tuned on internet, and after a while lag reappeared.
Resated PC > turn off internet > lag disappeared > exited UE > tuned on and off internet > fire UE > lag was there again
That’s all the tests I had time to do, and I’m still missing adding/manually allowing UE through windows 11 firewall. But I think at least in my case is ‘Internet Connection’ related, UE wants to connect but windows does not allow some parts of it, and I’m saying “some parts” because ‘quicksell bridge’ does run throught UE5.4, but that too is Veryyyyyyy laggy.
Also, I did that tests with loading a project created with a basic UE5.4 template, I did not tried to load a heavy project.
Perhaps I did not pay attention to it before, but when my Unreal Editor starts, it also displays a GeForce Experience Overlay. I found this strange and deactivated the overlay. Now, the program runs as smoothly as it did with previous versions. However, I will further investigate on this issue tomorrow.
I am unsure of how the GeForce Experience Overlay integrates into a program, so perhaps it was too demanding when other windows, such as a blueprint editor or animation blueprint editor window were open at the same time. I am unsure if this overlay was inactive in previous versions; I simply did not notice it before version 5.4.
Good luck in finding more clues so that we can determine who the culprit is or at least how to fix it
I take back what I said.
I’ve seen a lot improvement, but every 10 mins or so, starting PIE will just be 1-2FPS indefinitely, requiring me to stop and start it again to get usable frames. Solution not found for this.
I also use HDD for my projects, and 4.3 works perfectly fine with that.
Upon testing it again, disabling the Plugin Studio Telemetry has resolved the lag issue. Additionally, disabling TCP and UDP also seems to provide some additional improvement. However, it raises the question of why these actions slow down the Editor. Is the excessive ping for sending user data causing this issue, or is it a bug? This is not a new issue; it has been mentioned before as a potential solution for fixing a laggy Unreal Editor. However, this does not seem to be a problem in Unreal 4.3 for me. Is it related to the telemetry plugin or is it a new bug related to TCP/UDP messaging?
Can someone please help confirm my discovery or explain what the telemetry plugin is for?
Thanks in advance!
Edit: I enabled the telemetry plugin again and noticed that when starting PIE, it was running at a very low FPS and I was experiencing extreme lag, just like what you mentioned.
Disabling ‘GeForce Experience Overlay’ did absolutely nothing for me inUE 5.4, only turning off internet connection did something, but I haven’t done further tests to this because of lack of time
I can confirm that it is helpful to disconnect the internet while the telemetry plugin is still active. It only lags mildly when the internet connection is switched off. It’s not completely resolved, but it’s improved.
Disabling the previously mentioned plugins seems to be a good solution for now. The editor remains stable even with extended use. I hope a developer can figure out what to do about that.
None of those are really solutions even if they fix the lag/freeze, so unless a hot fix or UE5.4.1 is out really fast, I’ll have to keep working on 5.3.2 or ditch UE completely and go back to the stable Cryengine before my project gets to the point where it will be impossible to make the switch.
