Why Can't My Second GPU Without External Power Be Detected?
Asked by
TechSleuth42
I'm having trouble with my PC setup where my second GPU, which doesn't require external power, isn't being recognized in the BIOS. Here's my current configuration:
- CPU: Ryzen 7 9800X3D
- Motherboard: Gigabyte X870 AORUS Elite
- One NVMe drive installed in the top slot, and no additional drives
- First GPU (in the top PCIe slot): RTX 5070 Ti
- Second GPU (in the second PCIe slot): RX 6400 or RX 460
- I've also updated to the latest BIOS.
The issue is that neither of my non-powered GPUs are detected in the BIOS, though the fans spin up, indicating they receive power. They've been tested and do work in the primary x16 slot. I know the second slot works fine because it recognizes powered GPUs like the RX 480 or GTX 1080 without any issues.
I've already tried a number of troubleshooting methods: disabling PCIe ASPM, adjusting manual Gen3/Gen4 speeds, using legacy ROMs/CSM, disabling the iGPU, and trying bifurcation (switching from x16 to x8/x8), but nothing seems to help. I'm stumped—any ideas on why they're not working?
Answers
There might be a power limitation with the second PCIe slot that isn't enough for the GPUs to work properly. What purpose do you need the second GPU for? If you're aiming for a dual GPU setup, consider getting a GPU that requires external power, as that should work better for you.
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TechSleuth42: I initially thought it could be a power issue. I'm looking to set up GPU passthrough on Linux, and I need a low-cost DSC-capable card for display only. Looks like I might need to invest in something with external power after all.