Unable to Set ReBAR to 4G or Higher VRAM

[GSD4587]

Hi xCuri0, thx so much for sharing the UEFI ReBAR guide! I’m still a beginner with all this, so I was hoping you could help me out.

My motherboard is Gigabyte Z77-D3H rev1.1, CPU i7 3770k, GPU Intel A770 (16GB VRAM), 32GB of RAM (4x8GB), Windows 11. I followed the tutorial, added the DXE module in the BIOS, turned on Above 4G Decoding, and disabled CSM. Right now, without any patches, I can enable ReBAR up to 2GB (GPU-Z shows it’s all enabled, but the Intel Graphics Control Panel still says ReBAR is off). Whenever I try to set it to 4G or higher, the system won’t POST.

After applying the patches (including the USB3 patch), I just get a black screen and I can't access the BIOS anymore, but I belive my pc can get into Windows 11. Do I need to apply the DSDT patch for this to work? I’m trying to enable ReBAR for the full 16 GB of VRAM, but as a newbie, I’m still confused, even after reading the DSDT patch tutorial.

Would it be possible to send you my BIOS and have you take a look when you have the time? If that's too much to ask, I completely understand. Either way, I really appreciate all your work, and thanks again for the help! 🤝

[GSD4587]

Based on my computer's configuration, here are a few key BIOS settings to successfully enable 2G ReBAR:

1. All boot-related options must be set to UEFI Only.
2. CSM must be disabled.
3. Above 4G Decoding must be enabled.
4. In the Peripherals section, under PCIe Slot Configuration, you must select Auto.
   If these settings aren’t configured correctly, the system may fail to POST or could end up with a black screen. Other settings can be adjusted as needed.

So far, I’ve only been able to enable 2G VRAM ReBAR. Any attempt to use ReBAR with more than 4G of VRAM results in either a failure to POST or a black screen.