Unreal Engine Issues
Unreal Engine Issues
HZB Occlusion causes large stalls on the render thread
UE - Rendering Architecture - RHI - Oct 7, 2025HZB Occlusion causes large stalls (greater than 5ms seen) on the render thread due to an RHI flush. This is caused by the following code in FDynamicRHI::RHIMapStagingSurface_RenderThread which force ...
The Console Command list printed by using "Help" misses alot items in 5.6
UE - Rendering Architecture - RHI - Sep 12, 2025FD3D12BindlessResourceManager::GrowCPUHeap will cause GPU heap activation whether it's needed or not
UE - Rendering Architecture - RHI - Sep 11, 2025The ctor of FD3D12BindlessResourceManager implies that GPU heap activation is intended to occur lazily with ERHIBindlessConfiguration::RayTracingShaders, however any call to FD3D12BindlessResourceMa ...
Enabling STATS causes RenderThread to wait for GPU
UE - Rendering Architecture - RHI - Sep 10, 2025The licensee noticed that in Development builds, the Render thread times are suspiciously similar to GPU times, and the same thing happens when enabling FORCE_USE_STATS in Test configuration. The is ...
Missing PSO Precaches in the engine
UE - Rendering Architecture - RHI - Aug 20, 2025A licensee wanted to report some missing PSO Precaching they found, which they have fixed locally: 1. UCableComponent doesn't implement CollectPSOPrecacheData or call CheckPSOPrecachingAndBoostPri ...
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 ...
Bindless Textures in active use are able to be garbage collected
UE - Rendering Architecture - RHI - Jul 9, 2025It is possible for textures referenced in the bindless texture data assets that are actively used in materials being rendered in the active viewport to be garbage collected. This results in the mat ...
GPU event descriptions are not properly formatted in Insight
UE - Rendering Architecture - RHI - Jun 24, 2025Context Unreal Insights displays Timing Insights that can include GPU timing information. Rendering code such as FDeferredShadingSceneRenderer::RenderPrePass() generate such events.Problem Certain f ...
Fix up GPU breadcrumb labels for Intel performance analysers
UE - Rendering Architecture - RHI - Jun 13, 2025A licensee has brought up that the GPU breadcrumbs are incorrectly displayed with traces taken on the Intel GPU Analyzer tools (see screenshot). It looks like the format string is being passed on in ...
Scene with texture collection crashes when dumping a full memreport
UE - Rendering Architecture - RHI - May 28, 2025A licensee has reported that generating a full memreport of a packaged project which uses a texture collection leads to a crash. ...