nDisplay on LED wall GPU usage at 0 percent acc to task manager?

Development Cinematics & Media Virtual Production
1

Hi guys. Running UE5 over nDisplay on a LED wall. FPS are in an acceptable range (40-50 ish), but for a time I tried to run vMix on the same machine and it took a lot of performance away. I solved that by having a seperate vMix machine but in the process I noticed that task manager was showing Unreal as using 0 percent of the GPU. Is this normal or is it possible I set up something in a really bad way?

Win 10 AMD Ryzen 9 3900X 3.80 GHz 64GB RAM RTX3090 with latest game drivers, running via a Novastar H2 (UHD resolution set) to a 3840x1152 LED wall. UE5.1
Lumen and Nanite disabled (both were doing performance hits)

Thanks for any ideas!

Addition: CPU usage is around 25 percent for UE and RAM usage around 3GB.

2

Possible answer to my own question: Task Manager seems to not show UE GPU usage. Installed MSI Afterburner and it shows my GPU working at 97 percent, so apparently things are working just fine.