Proxmox VE 9.2.9 PCIe Passthrough Setup for NVIDIA T400 GPU

My Windows 11 VM running on Proxmox VE 9.2.9 has detected it's NVIDIA T400 GPU but not enabled the device. NVIDIA drivers are fully installed inside the guest.

I need a solid PCIe passthrough configuration so the card is exposed as a truly dedicated GPU for SOLIDWORKS 2026.

I have enabled IOMMU, edited grub, and checked vfio-pci, but I am not confident everything is optimised for VBS-enabled Windows 11.

I want to be sure the VM keeps all security features active, the host remains stable, and performance inside SOLIDWORKS reflects the card’s real capabilities.

Key deliverables:
• Verified kernel and grub settings on Proxmox 9.2.9 for NVIDIA T400 passthrough
• Correct VM configuration (machine type, BIOS, args, hugepages, etc.) compatible with VBS
• Confirmation that the GPU is running at full native speed inside the guest (GPU-Z or similar)
• A short write-up of the steps so I can repeat or recover the setup later

Please ensure you are experienced with fine-tuning vfio bindings, addressing error 43, and keeping VBS intact. Refer to the attached screenshots for clarity.