Hi all, posting this here since it’s specific to the 5.7 plugin and nDisplay. Hoping someone from NVIDIA or another VP studio has hit this.
Setup
UE 5.7, DLSS plugin reporting version 8.6.1 (NGX 310.6.0). nDisplay cluster, 2 nodes, mono render mode, single GPU per node (MaxGPUCount=1, confirmed via log). Nodes launched via Switchboard, running as UnrealEditor.exe in -game mode, joined to a Multi-User (Concert) session for live operation.
Issue
DLSS Super Resolution is enabled in the nDisplay viewport config. The node launches and renders correctly. The crash occurs specifically when the ICVFX camera (or related DisplayClusterConfigurationData) is modified live through the editor while connected over Multi-User. Within one tick of the synced edit landing on the node, it hard-crashes with:
Assertion failed: Upscaler->IsDLSSActive() [DLSSUpscaler.cpp] [Line: 876]
[Callstack] UnrealEditor-DLSS.dll!FDLSSSceneViewFamilyUpscaler::AddDLSSPass() [DLSSUpscaler.cpp:876]
[Callstack] UnrealEditor-DLSS.dll!FDLSSSceneViewFamilyUpscaler::AddPasses() [DLSSUpscaler.cpp:852]
What I’ve ruled out
This is consistent across multiple test passes, removing one variable at a time:
Frame Generation was loading initially and causing a separate device-removed crash (DXGI_ERROR_DEVICE_REMOVED, 887A002B) on a multi-GPU node. Setting r.Streamline.Load.DLSSG=0 and r.Streamline.Load.DeepDVC=0 fixed that crash entirely. This IsDLSSActive() assertion is a distinct, later issue, with FG confirmed off.
Tested r.SceneRenderTargetResizeMethod at both 0 and 2. No effect on this assertion.
Tested viewport screen percentage at 100 and 66. No effect.
Tested DLSS toggled live versus pre-enabled in the config before launch. Crashes in both cases. Pre-enabled, it crashes on the very first frame the moment any ICVFXCamera property syncs over Concert.
Tested with MaxGPUCount explicitly set to 1 and confirmed via log that multi-GPU was not enabling. Crash persists identically. This is not an mGPU issue.
Editor-launched nodes via the local “Launch nDisplay” button (not through Switchboard, not joined to Multi-User) do not crash. The crash only manifests with the node joined to a Concert/Multi-User session while DLSS is active and the ICVFX camera is edited.
My read
It looks like the DLSS plugin’s active-state flag for the upscaler isn’t surviving the view family rebuild that happens when an nDisplay/ICVFX camera property gets replicated through Multi-User. The check at line 876 then fails because the upscaler isn’t in the state AddDLSSPass expects, even though DLSS-SR reports as supported and enabled.
What I need
Live camera adjustment during a session is standard practice for our shoots, so this isn’t something I can just avoid. A few questions:
Is there a newer validated 5.7 build than 8.4.0 (Dec 2025) that addresses this? I want to confirm whether 8.6.1 is an official NVIDIA release or something else, since I’m not certain where it came from in our pipeline.
Has anyone else hit this specific Multi-User + ICVFXCamera + DLSS combination?
Is there a recommended cvar or workaround for forcing the upscaler to revalidate after a Concert-synced property change, short of disabling DLSS whenever the camera needs adjustment?
Happy to provide full node logs or the Switchboard config if it helps reproduce this. Thanks for any pointers.