u/Realtrickz

I’m running Microsoft Flight Simulator on a high-end Azure cloud workstation (Standard_NC36ds_xl_RTXPRO6000BSE_v6) equipped with an NVIDIA RTX PRO 6000 (Blackwell).

I’m struggling to get decent frame rates—I’m stuck at 30 FPS regardless of whether I use low or high settings. The in-game performance overlay consistently shows 'Limited by MainThread,' indicating a heavy CPU bottleneck.

To make matters more confusing, monitoring tools like MSI Afterburner and GPU-Z show '0' for all GPU metrics (clock speed, temp, usage), even though the machine is clearly running. I suspect the simulator isn't actually utilizing the GPU, or the virtualization layer is masking it.

Steps I’ve already taken:

- Confirmed Drivers: Ran nvidia-smi in the terminal, which confirms the driver is installed and the GPU is detected by the OS.

- Attempted Monitoring: Tried MSI Afterburner and GPU-Z, but they return blank/zero values for all sensor data (likely due to the SR-IOV virtualization used by Azure).

- Performance Tuning: Attempted to lower graphics settings and LOD sliders in MSFS, but FPS remains locked at 30, and the 'Limited by MainThread' bottleneck persists.

- Hardware Verification: Confirmed the VM is correctly provisioned as an NCv6-series instance with the Blackwell-based GPU.

Has anyone dealt with this 'Limited by MainThread' issue specifically on Azure GPU VMs? Is there a known way to force the simulator to prioritize GPU rendering over the CPU, or is this just an inherent limitation of the virtualization layer?"

I am experiencing a severe, system-wide performance cap on our newly deployed NVads A10 v5 series virtual machines. We have tested this across multiple sizes, including the NV12ads, NV18ads, and the full 36-core NV36ads configurations. On every single instance, the frame rate is completely hard-locked at 20 to 30 FPS. This bottleneck occurs regardless of the application's graphics settings, meaning switching from Ultra down to Low results in the exact same poor frame rate, which indicates a fundamental driver or hypervisor issue rather than a heavy graphics load.

To rule out standard software configuration issues, we have already executed full optimization loops. We manually installed the official NVIDIA vGPU 18 drivers directly from the official Microsoft N-series driver setup documentation. We also modified the NVIDIA Control Panel 3D settings to force maximum performance, turned on Hardware-Accelerated GPU Scheduling inside Windows, and configured Group Policy to force hardware graphics adapters for remote sessions. Furthermore, to entirely bypass standard Microsoft RDP limitations, we are utilizing Sunshine and Moonlight with dedicated NVENC hardware encoding.

Despite the high-end hardware, the instances act as though the GPU is un-licensed, severely throttled, or failing its handshake with the host hypervisor. We suspect the Windows graphics subsystem is routing the frame buffer through a basic virtualized driver instead of mapping directly to the dedicated A10 memory segments. Please if anyone knows how to diagnose why these specific A10 GRID drivers are failing to engage core clocks and properly uncap the frame buffer for our real-time 3D and cloud gaming workloads let me know.