[Problem] MSI X99A SLI PLUS won´t boot due to faulty RX 9070

System Overview

  • Motherboard: MSI X99A SLI PLUS (MS-7885)
  • CPU: Intel Xeon E5-2697Av4
  • BIOS Version: 7885v1F2(Beta version)
  • GPU (Old/Working): ASUS RX 5700 XT OC 8GB [also used for BIOS access]
  • GPU (New/Problematic): Gigabyte 9070 OC 16GB
  • RAM: 32GB DDR4
  • NVMe SSD: Present (removed during troubleshooting)
  • Monitor Connection: Verified directly to GPU during tests (used only HDMI)

Problem Description

  • The new Gigabyte 9070 OC 16GB GPU is not detected by the motherboard (no POST, no display output, not visible in UEFI). 1 long, 2 short beeps.
  • The old GPU works and allows access to BIOS.
  • Goal: Get the new GPU recognized and working on the X99A SLI PLUS.

Steps Already Taken

1. BIOS Settings Adjustments

  • Enabled “Above 4G Decoding” in BIOS.
  • Set PEG2 (PCI_E1/E5, primary GPU slot) to “Gen3” (instead of Auto) to force PCIe 3.0 compatibility.
  • Left PEG0 and PEG1 on “Auto”.
  • M.2 Source Link: Set to Auto.
  • M.2 PCH Strap: Set to M.2 PCH SATA.
  • PCI Latency Timer: 32 PCI Bus Clocks (default).
  • Screenshot of current settings attached:
    ![BIOS Screenshot]1

2. Hardware Troubleshooting

  • Removed NVMe SSD to eliminate PCIe lane/resource conflicts.
  • Reseated GPU and verified all power connections.
  • Tested monitor and cables directly to the new GPU.

3. BIOS/UEFI Maintenance

  • Updated to latest available BIOS for the motherboard.
  • Cleared CMOS and reapplied settings after changes.
  • Tried both UEFI and CSM/Legacy boot modes (where available).

4. Other Attempts

  • Tested the new GPU in another system to confirm it is functional.
  • Tested other PCIe slots on the motherboard.

Results

  • No detection of the Gigabyte 9070 OC 16GB GPU in any configuration.
  • Old GPU continues to work, confirming the motherboard and slots are functional.
  • All recommended BIOS settings for modern GPU compatibility (Above 4G Decoding, PCIe Gen3, NVMe removal) have been tried.
  • No success with toggling CSM.
  • No POST or display output with the new GPU installed.

Request for Help

  • Suspected Issue: Fundamental compatibility problem between modern UEFI-only GPUs and the X99A SLI PLUS (MS-7885) BIOS/firmware.
  • Seeking:
    • Modded or unlocked BIOS for MS-7885 that exposes additional PCIe or UEFI settings (e.g., IntelRCSetup menu, advanced MMIO/PCI resource options).
    • Guidance or files from users who have successfully run modern GPUs (RDNA3/4, RTX 40 series, etc.) on X99A boards.
    • Any further troubleshooting steps or BIOS modding advice.

Screenshot of current PCI Subsystem Settings:
![BIOS Screenshot]1

Thank you for any assistance or shared experience!

—1: https://pplx-res.cloudinary.com/image/upload/v1746383179/user_uploads/34140370/RMybpaqUwCrHlEk/selected_image_5368676460161664951.jpg


Edit by Fernando: Thread title customized and shortened

Problem solved!

Solution: Card went back to dealer. Ordered a proper nvidia card. 5070ti works out of the box.

thread can be closed.

I see that the problem has already been solved, but I want to leave a comment
I encountered a problem with the RX 9060 XT on X99a SLI in Windows 10 and Server 2022. It looked like the video driver was not working. As it turned out, the issue was present ReBar being enabled.
As soon as the Bar size exceeds 8Gb, the driver stops working. What is most interesting, everything works in Windows 11. It also works in 10 without ReBar enabled. And it works with ReBar enabled on an old video card with 8Gb VRAM. I have never been able to find out what the root cause of the problem is.