Question System only displays video if CSM is enabled?


Aug 26, 2013
I recently built a computer for a friend. Everything is fine except I cant get the GPU to display video in UEFI mode?

Here are the specs:
MSI B550-a pro
Ryzen 5 3600
GTX 1660 Super
2x Corsair Vengance 3200
650W Corsair Power supply
500 WD Blue NVME

Very weird issue. So I was able to determine that the system does not display video with UEFI enabled. I made sure all cables were installed properly. Once I noticed that there was no video, I swapped out the 1660 with an old 730 I have. Oddly enough, with the 730 installed the system will boot up and display video with a message "This graphics chip does not support UEFI, CSM will be enabled." Once CSM is enabled I can put the 1660 super back into the system and run it all day long with windows. But the moment I enable UEFI and reboot, the system wont even display the splash msi logo but will still post according to the debug led. I updated the bios to the latest version, ran a memtest which tested fine and checked for bent pins on the cpu. Every thing seems fine but even after all of that the issue still persists. But the system runs great with CSM enabled.

Any ideas or help would be greatly appreciated!
Bad board or GPU? Temps are great!