I want to enable resize bar

So I'm sure that everything is good to get resize bar . I have a gtx 1660 evga ryzen 5 3400g and b450m ds3h. This morning i tried to update the gpu bios flash and guess what happened my gpu stopped working. so i bought a new one today which is the gtx 1660(before i had rx 580 4gb), so its bricked and gone forever. However i managed to disable csm without bootlooping. so now the problem is that i cant find the option for resize bar. and everything in gpu z say yes for resize bar except the resize bar enabled in bios. So i dont know why the options is not there.

Dear Ilyasse Aziz,

Thank you for reaching out regarding your issue with enabling Resizable BAR (ReBAR) and Smart Access Memory (SAM) on your system.

I understand the frustration of trying to disable CSM (Compatibility Support Module) and having it revert after rebooting.

Let's go through some steps to diagnose and hopefully resolve this issue.

Step 1: Verify System Requirements

• CPU: Ensure your AMD Ryzen 3000/5000 series or Intel 10th/11th gen (or newer) processor supports Resizable BAR/SAM.
• GPU: Your graphics card must support Resizable BAR. This is typically available on NVIDIA GeForce RTX 30 series or AMD Radeon RX 6000 series (or newer).
• Motherboard: Your motherboard's BIOS must support Resizable BAR. Make sure that your BIOS is up to date.

Step 2: Update BIOS and Firmware

• Motherboard: Visit the support page for your motherboard, find your model, and download the latest BIOS update. Follow the instructions carefully to update it.
• GPU: Check your GPU manufacturer's website (NVIDIA or AMD) for the latest firmware updates. For NVIDIA, there is a Resizable BAR firmware update tool that you can use.

Step 3: Modify BIOS Settings

1. Disable CSM:
   • Enter BIOS by pressing the appropriate key (usually DEL or F2) during startup.
   • Go to the Boot tab.
   • Locate CSM (Compatibility Support Module) and set it to Disabled.
2. Enable UEFI and Secure Boot:
   • In the Boot tab, ensure Boot Mode/UEFI Mode is set to UEFI.
   • Set Secure Boot to Enabled.
3. Enable Above 4G Decoding:
   • Go to the Advanced tab.
   • Find Above 4G Decoding and set it to Enabled.
4. Enable Resizable BAR/SAM:
   • In the Advanced tab, look for PCI Subsystem Settings.
   • Set Resizable BAR Support and/or SAM to Enabled.
5. Save your changes and exit BIOS. Your system should boot with the new settings.

Disclaimer: If you are going to modify BIOS Settings, please back up all your personal files first to ensure you do not lose data.

Step 4: Troubleshooting Boot Loop

If your system goes into a reboot loop after disabling CSM, follow these steps:

• Disconnect any non-essential drives (only keep your boot drive connected) to isolate the issue.
• Reset BIOS settings to default, then reconfigure the required settings.
• Ensure that your GPU and monitor are compatible with UEFI boot. Some older configurations may cause boot issues with UEFI.

Step 5: Verify Windows Boot Configuration

If everything checks out but you are still experiencing issues, you may need to repair the boot configuration:

1. Boot from a Windows installation media (USB or DVD).
2. Choose Repair your computer > Troubleshoot > Advanced options > Command Prompt.
3. In the Command Prompt, enter the following commands:

    bootrec /fixmbr
   
    bootrec /fixboot
   
    bootrec /rebuildbcd
   

If none of these steps resolve the issue, I recommend reaching out to your motherboard or GPU manufacturer for further assistance, as this could be a hardware-related problem rather than a Windows issue.

Please let me know if any of these steps help or if you need further clarification. Thank you for your patience and cooperation!

Best Regards,

Martin | Microsoft Community Support Specialist