So, I recently upgraded my GPU from a 1660 TI to a 4070 TI. Everything went fine the first time I swapped them out. I even played a game to test, and it seemed to work. But after restarting, my PC just won’t detect the new GPU anymore. I’ve tried all sorts of things like checking the power cables, messing with BIOS settings, and even swapping cables and monitors, but no luck. The old 1660 TI works just fine, though. I’m stumped at this point! Does anyone have suggestions? 
If you’re not sure about what BIOS settings you changed earlier, maybe try doing a CMOS reset. You’ll find the instructions on page 1-17 of your motherboard manual. Just be aware that you’ll have to re-enable your XMP/EXPO profile afterward! 
I tried doing the CMOS reset, but unfortunately, no change. Still getting no output from the GPU, and the VGA debug light on my motherboard is still on. 
Hmm, I’m leaning towards ‘insufficient power’ as the issue. Does your GPU have 2x6 or 2x8 power leads? Are they split from the PSU or using two separate connections? If not, try the latter. Also, maybe consider upgrading to a more powerful PSU, like 850W, just to make sure your GPU gets enough juice.
Yeah, the connector going into the GPU is 2x6, and I’m using two separate cables plugged into two different PSU slots, just as recommended. I don’t think I need a more powerful PSU though—PCPartPicker says my build only needs 476W, and people have used this PSU with much more powerful cards without issues. I’m thinking it’s more of a power delivery issue, though. I’ve ordered a new splitter cable, so I’ll see if that helps when it arrives tomorrow. 
Gotcha! Keep us updated on how the new splitter cable works out. It’s good that you’re troubleshooting everything. Fingers crossed!
I had some weird issues with a motherboard once, even RMA’d it. In the end, it turned out to be a loose connection somewhere. You might want to double-check all your connections, especially the ones to your GPU and PSU. Could be something simple like that!
Thanks for the suggestion! I’ll definitely check all the connections again. Hopefully it’s just something loose. I’ll update if I find anything.
No problem! Let me know if anything works or if you run into more issues. 
Hopefully, it’s an easy fix!