We are unable to render our project with MRG path tracing in Unreal 5.6 on GPUs with 24G of VRAM, while rendering in 5.5 works fine. We have had some success rendering on 5090 RTX cards that have 32G of VRAM. Has anything changed with memory consumption in path tracer? It seems our scenes even with…

Steps to Reproduce Render the same scene using MRG with Path Tracer on 5.5 and 5.6, including Nanite geometry with r.RayTracing.Nanite.Mode 1.

Hi! Just passersby here who works with 4090/5090 using path tracer too - are you using Extended GPU Timeout Detection (TdrDelay) in windows registry by any chance? Exceeding VRAM is not optimal ofcourse, but across many unreal versions and rendering primarily on path tracer, we had only rare cases …

Hello, Can you attach Memory Insights captures from UE 5.5 and 5.6 for us to compare? That will likely reveal where the memory is going. Launch the Editor with -trace=default,memory Enable Capture Unreal Insights Trace in MRQ > Settings > Debug Options Render a frame If you’re also seeing higher…

Here you go. I rendered a single frame in 5.5, then opened a copy of the project in 5.6 and rendered the same frame.

BTW it just occurred to me that the AWS G6e nodes we use that are crashing have 48G of VRAM, so I’m not sure this is an out of memory issue: NVIDIA 4090 RTX 24GB - Crashes NVIDIA L40S 48GB - Crashes NVIDIA 5090 RTX 32GB - Renders fine

For some reason the attached Insights Traces didn’t contain the memory insights , just the default performance (CPU/GPU) data, can you confirm you’re launching the Editor with -trace=default,memory? This should help us determine where the memory is going. BTW it just occurred to me that the AWS G6e…

5.6 Path Tracing Crash / Increased VRAM Usage

Development Rendering

UnrealTD (UnrealTD) April 16, 2026, 11:30am 8

As you are using the CVar r.RayTracing.Nanite.Mode 1, you should look at this post to resolve your VRAM usage.
You can see the VRAM usage with the tool Render Resource Viewer (menu Tools > Render Resource Viewer).