Precision T7920 GeForce GTX issue

I have got a new Dell Precision T7920 workstation and tried to use my old GTX 970 card, the screen stays black during post and only works after windows completely boots up, i have also tried GTX 1650 Super, same issue.

Drivers are up to date, tried latest BIOS update and previous version same issue occur. By using an entry level GTX 710 everything seems to work well, did anyone face a similar issue or have an idea what might be the issue?

I know all the models i mentioned aren't listed under the supported gpu models for T7920