Question Possible to use Resizable Bar & CSM for Dual Booting?

[Axcel34]

I recently built a new computer and decided to try out one of Intel's Arc a770 cards. After figuring out how to get Resizable Bar enabled in the BIOS (ReBar is new to me so I had to learn what all it needed to function), I discovered that CSM support needs to be disabled in my BIOS in order to keep it on.

I dual boot Win10 and Linux, the only way I am able to see my Linux drive in my boot order is if I have CSM enabled, making this seem like a choice between my single Windows drive & my a770 or the ability to dual boot (with poor graphical performance to boot).

TL;DR: I have to disable CSM to get performance out of my Intel GPU but need CSM enabled to access both of my boot drives. Looking for a way to have both.

Apologies if I left out any information. Please let me know if there is anything else I should add.

Intel Core i7-12700KF 3.6 GHz 12-Core CPU
Gigabyte B760M Gaming Plus Wi-Fi DDR4 Micro ATX LGA1700 Motherboard
Corsair Vengeance LPX 32GB (2 x 16GB) DDR4-3600 CL18 Memory
Sparkle ROC OC Arc A770 16GB Video Card

 

[Misgar]

Reminds me of needing to switch off AHCI support to boot XP instead of Windows 7 (and yes I know you can patch XP on-the-fly with the relevant drivers).

You're not going to like this, but can you disable CSM, then reinstall Linux (and possibly) Windows 10? I'd be inclined to fit a couple of spare SSDs for this experiment.

I have some Windows 10 installs on older CSM/MBR systems and others on newer UEFI/GPT systems.

Disconnect your existing Linux and Windows drives, before messing about with fresh OS installs. You don't want the new UEFI boot partitions ending up on the old MBR? drives.