I recently bought a used PowerColor Red Devil 6900xt to replace my old GTX1070. I have a Chieftec Navitas 850W PSU which has two 8-pin slots.
The card has three 8-pin slots so at first I ran the card in a setup of 1x8pin to 1x8pin and the other two slots i had daisy chained.
This card has a physical silent and an OC mode bios switch on the card and just to be sure I used the silent mode because of the daisy chaining.
At this point everything was working fine.
As I had heard that daisy chaining is generally frowned upon I though I could just buy a 2x6pin to 1x8pin adapter and connect my GPU "properly" and use the OC mode.
I connected all the cables put the card to OC mode and started the PC, which now didn't boot anymore and the VGA light is on at my motherboard. However the LEDs on the card do turn on.
Switching back to the silent mode and old cable set-up also didn't fix the booting
When I put in my old GPU the PC boots again so it's pretty likely I busted the GPU. However, there is no sign on the card or the power connectors of any damage?
My question is, could there be any way that the card is still working? Would it be worth to try to go to a repair shop? Is there a way to diagnose or try to repair the GPU myself? Could it maybe actually be an issue I didn't think about?