Enabling resizable bar and 4G, CSM is off = blank screen ?

[Abel_Mathew]

I recently upgraded from the Nvidia Quadro T600 to the Intel Arc A750. I tried enabling resizable bar and turning CSM off, but it resulted in a blank screen with the message ‘cable not connected,’ even though the HDMI cable was properly connected.

I then reset my motherboard BIOS (Gigabyte B550M DS3H) and updated it to the latest version (F19). However, when I attempted to enable resizable bar and disable CSM again, I encountered the same black screen issue, but this time the ‘cable not connected’ message didn’t appear—it was completely blank.

My system is running Windows 11, fully updated, and the Intel graphics driver is up to date. Notably, I didn’t enable resizable bar previously when I was using the Nvidia Quadro T600.

Could you please guide me on how to enable resizable bar without encountering any issues? I’ve attached a screenshot of my system specifications for reference.

[Pratik_MD]

That's a know issue with some arc cards, they do not fully support UEFI. Are you able to boot into windows ?

[Abel_Mathew]

No, I Can't when I enable resizable bar, when it is disabled I can be able to boot into windows.

Do you know any solutions?

[Pratik_MD]

Check whether your boot drive is in GPT or MBR. If you have installed windows when CSM was enabled then it's probably its in MBR mode. And if you want to use rebar which obviously requires CSM to be disabled. Please confirm this first.

.
Refer this
How to check if a disk uses GPT or MBR
https://youtu.be/hJIC_SrpWRs?si=kgE_zMaLeIJ8hg6q

And I can see secure boot is disabled, enable it and choose  appropriate boot device.