5700XT works, but no video output on specific motherboard.

[Byakapro]

So my system (Aorus B550 pro-p mobo, ryzen 5 3600, 5700XT GPU, 550w cooler master PSU) was posting and booting into windows perfectly fine. But when I swapped out the power supply for a 750w nzxt unit there is no video output. This problem persists when swapping the old psu back in. I've tested all the parts individually using another system and everything functions perfectly. BIOS is up to date. Tried resetting CMOS to no avail. I've narrowed it down to the graphics card. The system works perfectly when I exchange the 5700XT for a 1070, and the 5700XT works perfectly when put into the system the 1070 was in. Why is there no video output when I put them together?? Any ideas? 

[Cela1]

Did the 1070 use the same cables as the 5700XT did when testing? (e.g. the 1070 FE only needs 1x 8-pin , while 5700XT needs 1x 8-pin and 1x 6-pin) and such it could be a broken cable?

[Byakapro]

Just now, Cela1 said:

Did the 1070 use the same cables as the 5700XT did when testing? (e.g. the 1070 FE only needs 1x 8-pin , while 5700XT needs 1x 8-pin and 1x 6-pin) and such it could be a broken cable?

Yes they used the same cables. I've tried various cables and power supplies to make sure the power supply was not the problem. As well as using that power supply in a whole other system with the 5700XT in it

[Cela1]

3 minutes ago, Byakapro said:

Yes they used the same cables. I've tried various cables and power supplies to make sure the power supply was not the problem. As well as using that power supply in a whole other system with the 5700XT in it

Strange. The only other option I can think of is PCIe 4 incompatibility (But that SHOULD never be an issue as PCIe is fully backwards compatible).

[Byakapro]

6 minutes ago, Cela1 said:

Strange. The only other option I can think of is PCIe 4 incompatibility (But that SHOULD never be an issue as PCIe is fully backwards compatible)

The strangest part to me is that this combination of parts was working perfectly fine together before I took it apart. 

[Fasauceome]

Do you have space in your case to use the lower PCIe slot to test? Not optimal but can possibly help diagnose the issue.

[Cela1]

Just now, Byakapro said:

The strangest part to me is that this combination of parts was working perfectly fine together before I took it apart. 

Yeah, that's strange alright 

 

The solution? Never modify any PC that is currently working ever.

 

Unfortunately the only semi-solution I can recommend atm is RMA whatever you can .

[Heliian]

I'm going to go with driver issue or bad ground.

 

Bios up to date and other drivers up to date? 

[Byakapro]

20 minutes ago, Heliian said:

I'm going to go with driver issue or bad ground.

 

Bios up to date and other drivers up to date? 

Yes. All up to date

[Byakapro]

28 minutes ago, Fasauceome said:

Do you have space in your case to use the lower PCIe slot to test? Not optimal but can possibly help diagnose the issue.

That might be worth a shot. I'll see what happens. 

[Byakapro]

Someway somehow setting the PCIe 16x to gen 3 has fixed my issue. I tested the three other cards I have on hand and they all worked fine with gen 3 and gen 4, but for some reason this specific power color Red Devil 5700XT just will not work on gen 4 on this motherboard. Well it's working now so I can't really complain, just want to understand why haha. Thanks everyone for all the help!