Yeah, you've gotta tell us what you're working with. If it's a GeForce, I'm out of ideas. Try and find some resources from other people who've gotten it working, but AFAIK it's a really hard nut to crack, that's why I bought a Quadro.
@AveryFreeman I did hypervisor.cpuid.v0=false before even installing the GPU in the VM. I Started the System with it, and shut it down right after it. After that I installed the PCI Device and added pciPassthru.use64bitMMIO = "TRUE", pciPassthru1.msiEnabled = "FALSE" and pciPassthru0.msiEnabled = "FALSE"
Then I started the VM again and Installed the Device Drivers. If I Keep the SVGA then I will only get Bluescreens at the windows Start. I deinstalled the Nvidia Drivers now, reinstalled them, then they work for this short period (No code 43) but after one reboot Code 43 appears again.
I even tried the ACS Check , but that also didn't help. I am on the Newest Windows Version.
2 Geforces working fine here in my setup and happy with it for multiple months. EVGA 1070 for Linux Mint and ASUS 1080Ti for gaming. No passthru map adjustments needed. Depends on your hardware.
Typing this on it. Might only did ACS parameter for USB issues.