Unreal Engine Issues
Unreal Engine Issues
Significant Performance Drop During Play While Behavior Tree is Open
UE - AI - May 18, 2016Attempting to play in editor, standalone, or VR Preview when a behavior tree that is running is open will cause a significant performance decrease. The framerate drops from ~120 to ~80 fps while the ...
Performance slowdown when ray tracing is disabled due to SetResidencyPriority
UE - Rendering - Architecture - RHI - Jul 17, 2025When a game is compiled with ray tracing disabled (D3D12_RHI_RAYTRACING=0) and the GPU the game is running on becomes low on VRAM, frame time is negatively impacted and doesn't recover. The D3D12_RH ...
Performance regression from 4.10 to 4.11 on Sony Xperia M4 Aqua
UE - Platform - Mobile - May 27, 2016User reports that on the Sony Xperia M4 the FPS have decreased from about 25 down to 5 after upgrading to 4.11. ...
Performance issues when a Render target is added to Spectator screen (VR) in a packaged game
UE - Platform - XR - Feb 20, 2019Performance issues when a Render target is added to Spectator screen (VR) in a packaged game ...
VirtualTexture performance is much worse on SM6 than SM5
UE - Graphics Features - Feb 19, 2023Performing a hot reload on a project that contains an FStringAssetReference will crash the Editor.
UE - Foundation - Core - Mar 10, 2015Performing a hot reload on a project that contains an FStringAssetReference inside a struct results in a crash. This was reported to work fine in 4.6.1, but I was unable to verify that is the case. ...
Instanced static meshes fire an erroneous performance assert about loose parameters.
UE - Graphics Features - Sep 4, 2019"This ensure is intended to catch regressions where rendering programmers add a loose parameter to LocalVertexFactory, breaking dynamic instancing on regular static meshes. InstancedStaticMeshes c ...
AssetRegistry has poor performance when a large map is resaved: Directory IO
UE - Core - Data Pipeline - Cooker - Mar 10, 2025IO cost of directory scans is one of the costs present in the AssetRegistry when a large map is resaved. Maps can have external actors which all have to be rescanned and reported to the map for incl ...
Crash and Performance issues when Generating Foliage using the Procedural Foliage Volume
UE - World Creation - Worldbuilding Tools - Foliage - Feb 14, 2017Users are reporting crashes and poor performance when generating foliage using the Experimental Procedural Foliage Volume tool. Regression? Yes, this does not occur in the previous engine version o ...
Planar Reflections Cause Big Performance Hit In Packaged VR Projects
UE - Platform - XR - Jan 22, 2020Planar reflections notably lower performance in packaged VR project. Linked is an example project and an example package. [Link Removed]. This was tested on a Vive Pro and Oculus Rift(not Rift S). ...