I also second JayDDees recommendation about testing with a different GPU if available or testing the GPU in a different mainboard. But I wouldn't rule out power yet, these mainboards are weird af lol.
Cheers and good luck!
It's always risky to assume. Anyway it can be tested by using a riser and drawing power directly from the PSU.
If the PSU itself was the problem it wouldn't boot with the GPU inserted. But it doesn't hurt to try a different PSU
if one is available.
If it's not the GPU and not the PSU the only thing left is the the PCIe slot(s) on the motherboard.
JayDDee,
You are going to think I am crazy, but I bought a brand new Seasonic 850 PSU from Best Buy, and was delivered yesterday. Tested in test rig yesterday with the known working Zotac 1070. I totally agree, I am pretty sure i tested everything before using it on this unknown (to me) motherboard.
This thread was from 4 years ago, but it seems a group of people on here were starting with early versions of this motherboard from China, and it seems they needed power to all Molex connectors (I guess the newer versions use 6 pin connectors) next to the GPU's even if the GPU slot was empty...............does this make sense?