I'm troubleshooting a highly reproducible PCIe problem with an ASRock B850I Lightning WiFi, Ryzen 7 9850X3D, RTX 5070 12GB, 32GB of DDR5, and a Corsair RM850. With the GPU set to PCIe 4.0 x16, the system develops severe mouse lag, PCIe lane errors appear in HWiNFO, and the computer freezes or reboots within about two minutes. I tested two RTX 5070 cards from different manufacturers, and both behaved the same way. An older GTX 1050 Ti appeared stable. PCIe 4.0 x8 seems stable, while PCIe 3.0 x16 also avoids crashing but still reports errors. I also tested PCIe 5.0 x8, which remained stable and showed no lane errors, whereas x16 continued to produce errors and crashes. I have tried BIOS defaults, the latest BIOS, clean Windows installations, different storage drives and drivers, DDU, reseating the GPU, different DisplayPort connections, and no riser cable. A new power supply is being tested as well. The motherboard's PCIe retention clip was initially stuck during installation but was reattached and now functions normally. If the new PSU does not change anything, does this point strongly enough to a faulty motherboard, PCIe slot, traces, CPU socket contact, or PCIe controller to justify an RMA? Would it be reasonable to keep using the card at PCIe 4.0 x8, or should I replace the board? Are there any additional BIOS settings or diagnostic tests worth trying first?
1 Answer
I would replace or RMA the motherboard rather than accept running at x8. A system that cannot reliably operate the GPU at its expected x16 link width is not behaving correctly, and the fact that multiple cards show the same failure points more toward the board or PCIe path than the graphics card. The retention-clip issue may also complicate an RMA, even if you were able to reattach it successfully.
Thanks, that makes sense. If the replacement board has the same problem, I’ll test another model as well rather than relying on x8 permanently. I’m still deciding whether to get the same board again or switch to a comparable B850 model from another manufacturer.