W480 IOMMU error, white screen and AMD driver install fail

[CDR_Xavier]

My W480 have had issues with the installation of AMD graphics drivers. I have tried two fresh installs of Windows 10, installing in safe mode, installing the GPU driver when the display is not connected to the GPU. I have tried three different versions of drivers for the three different tiers of cards I have.

 

Furthermore, when I enable IOMMU in BIOS, the entire screen will become white, regardless of what GPU I have used (I have tested both RX470s, I have also tested two other Radeon HD 4650s, and even the integrated onboard GPU). All 6 of them causes the BIOS boot screen to become completely white, and the BIOS to boot-loop.

 

There were also a lot of Windows WHEA errors related to IOMMU faults and so on. Also sometimes "above 4G encoding" would hang the entire computer.

The memory passed all tests, so thats unlikely the issue. I also re-flashed the BIOS image, which helped improve things (instead of a all-white screen when the logo shows, the logo and the "press del to enter setup" become white boxes and other area remain black.)

I have talked to a Gigabyte representative and RMAed it, but Gigabyte says there are no problem at all with the board, which I doubt.
 

The board is very slightly bent (maybe 1/8 off across the entire length of board)

What could be wrong?

 

 

 

W480 Vision W, i5-10600K (I dont think it has ever been overclocked at all), 2666 DDR4 Vengance.