Your passthrough may not work as intented.   On proxmox you would follow the following steps :   https://pve.proxmox.com/wiki/PCI_Passthrough#GPU_Passthrough   Is everything correctly blacklisted on proxmox host ? Did you configure correctly your proxmox grub kernel command line ? Did you confirmed the IOMMU are OK and the GPU has its own IOMMU number ?   On ESXi, I can't tell, I don't have it anymore, and never tried to GPU passthrough.