My PC was running normally until it suddenly began stopping at the motherboard logo during startup. I cleared the CMOS, moved the RAM modules between slots, and even performed a fresh Windows 11 installation, but the issue remains. The system boots and works normally using the CPU's integrated graphics, but it hangs at the motherboard screen as soon as the RTX 4070 Super is installed. Removing Nvidia drivers did not change anything, so the problem appears to occur before Windows loads. The system uses an ASRock B650I Lightning ITX motherboard, Ryzen 7 9800X3D, Zotac RTX 4070 Super, 32GB of G.SKILL Trident Z5 DDR5-6400, a Corsair MP700 2TB NVMe SSD, and a Corsair SF1000 power supply. The GPU's fans and lighting turn on. I also removed the Fractal Terra's riser cable and connected the card directly to the motherboard, with no change. Setting PCIe to Gen 4 manually did not help. I tried updating the BIOS with a FAT32-formatted 16GB USB drive, but the board reported "No Image File Found." What else should I test to determine whether the problem is the GPU, motherboard, power supply, or BIOS?
3 Answers
Because this is an ITX build, make sure the card is being tested without the riser cable, as a faulty or incompatible riser can cause exactly this kind of startup problem. You already tried a direct connection, which is useful. If the issue is still identical, try forcing PCIe Gen 4 or Gen 3 in the BIOS, load BIOS defaults again, and check that the card is fully inserted without case pressure or alignment problems.
Since the PC displays normally through the 9800X3D’s integrated graphics and only hangs when the discrete card is installed, the GPU, its power connection, the PCIe slot, or the motherboard’s PCIe initialization are the main suspects. Check the motherboard’s diagnostic LEDs during the freeze, confirm the GPU power cable is fully seated, and try booting with another graphics card if possible. Testing the 4070 Super in another known-good system would be even more conclusive. Don’t hot-plug the card while the computer is running.
The BIOS update error may simply mean the file is not the exact image expected by the board. Verify that the BIOS file is for the precise B650I Lightning WiFi model and revision, extract the file rather than leaving it inside a ZIP archive, and follow ASRock’s naming and USB-port instructions. A BIOS flashback feature may require a specific filename and port. Do not force a BIOS update with an image for a different model. Also, DDR5-6400 can sometimes cause instability on AM5, so test with one memory stick at default settings while troubleshooting, although that is less likely if the machine works consistently with the GPU removed.

The GPU fans and lighting turning on only confirms that it is receiving some power; it does not prove that the card is initializing correctly.