Ray Tracing 8K | Crashing UE4 4.23

Sep 16, 2020.Knowledge

Ray tracing can be quite a heavy task, even for some high-end PCs. If you are experiencing crashes at high resolutions similar to the below images, please attempt the suggested fix.

Application is running at 8K resolution and has ray traced lighting.


GPU: RTX 8000 Quadro (48GB VRAM) (Driver: 431.86)

CPU: AMD Ryzen Threadripper 2950X 16-Core ~3.5GHz

OS: Windows 10 Pro 64-bit (Build 17763)

Samples Per Pixel attempted:

Skylight: 64

Reflection: 64

Translucency: 64

Ambient Occlusion: 16

Unable to render greater than ~8 Samples Per Pixel without a crash.

There is a changelist that was added to 4.23 for GI tiling here: 8096515

For reference, the bulk of the code diff in RayTracingGlobalIllumination.cpp: