When 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_RHI_RAYTRACING can also be changed with the following setting in BaseEngine.ini or DefaultEngine.ini
{{[/Script/WindowsTargetPlatform.WindowsTargetSettings]
bEnableRayTracing }}
The issue appears to be due to FD3D12Adapter::SetResidencyPriority being a no-op when D3D12_RHI_RAYTRACING is off. Bringing FD3D12Device::GetDevice5() out of the ifdef so D3D12_RHI_RAYTRACING is not required to call SetResidencyPriority() causes performance to behave as expected.
1. Disable D3D12_RHI_RAYTRACING and compile
2. Run a game that consumes a lot of memory (higher resolution, larger texture pool budget etc) on a GPU with 8GB
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-305620 in the post.
| 0 |
| Component | UE - Rendering Architecture - RHI |
|---|---|
| Affects Versions | 5.4, 5.5 |
| Created | Jul 17, 2025 |
|---|---|
| Updated | Jul 17, 2025 |