Question System Fails to Power On with GPU Connected

[Hernán Brué]

Hello! I've been having the following problem for months, and honestly, I don't have any other option but to see if we can resolve it together. (sorry my english!)

SETUP:
- Micro Intel Core i9 12900K LGA1700Mother Asus Strix Z690-F Gaming Wifi LGA1700
- 2x16 Kingston Fury Beast 16GB DDR5 5600Mhz
- SSD Aorus 500GB M.2. Pcie Gen 4
- PSU Corsair RM850X 850W 80+Gold
- WaterCooler CoolerMaster ML360L V2 ARGB
- Zotac GeForce RTX 3080 12GB GDDR6X Trinity LHR

PROBLEM:
The system doesn't turn on, not even the BIOS. It stays on a black screen, and the motherboard's error lights alternate between yellow and red (mostly yellow, occasionally changing to red and back). The only way to power it on is by pressing the Reset CMOS button on the motherboard or unpluging the GPU.

TESTED:
- Initially, there was a suspicion of a problem with the RAM modules, which were tested by the official service and found no faults.
- The motherboard was then tested using a burning test, and everything was functioning correctly. There were no faulty slots or any physical issues.
- I sent the GPU for testing to the technical service, and after a month of testing it with similar setups, including AMD systems, no faults were found.

It seems like a BIOS config problem but I'm not sure.

IMPORTANT:
While I don't have the GPU installed, the system works perfectly. Every time I remove the GPU and reinsert it, the system works fine (i.e., it starts without any problems after turning it off) for one day and then fails again. If I disconnect the GPU (8 pins) and reconnect it (without removing it from the PCI slot), the system works fine again for one day. If I update the drivers, it starts failing again, but if I restart either through CMOS or by disconnecting the power, it starts working again.
Initially, after all the tests, it seemed like a physical problem, but it appears not to be. I even tried shutting down the PC, disconnecting it to discharge all the capacitors properly, and then it starts up but it fails again afterwards.

I would appreciate your assistance or help because I don't know what else to do!

 

[Aeacus]

disconnecting it to discharge all the capacitors properly

You can not discharge the caps on command. Especially when you disconnect the PC from the mains. Caps hold power in them for a long time. Heck, caps in PSU carry lethal charge for several years.

While I don't have the GPU installed, the system works perfectly.

At this point, i'd see 2 options:
1. Replace GPU.
2. Replace PSU.

#1 is easy to test. Just get another dedicated GPU, known to work and look if your system can cope with that.

#2 is more likely culprit. While 850W is enough for RTX 3080, we can not rule out PSU issue. Especially since you haven't tested with 2nd PSU.

What i'd do, is 1st borrow another RTX 3080. Maybe MSI or EVGA model. And then try it in your system. If system still throws a fit, i'd get new PSU. 1kW to be safe and Seasonic PRIME TX-1000, for top-notch build quality (better than Corsair RMx series).

 

[Hernán Brué]

Thanks! I will try the options you mention and keep you updated! I find it strange that it the GPU can be the problem because it was tested in similar setups and it did not give problems.

 

[geofelt]

Your symptoms might indicate that you have not properly connected both 8 pin motherboard eatx connectors.

 

[Aeacus]

I find it strange that it the GPU can be the problem because it was tested in similar setups and it did not give problems.

Not all hardware works in all and every build. While it should, it just won't.

Common example would be RAM, which for e.g DDR4 and at speeds of 3200 Mhz would work fine in one system, but same RAM on another system and it won't be stable past 2667 Mhz. <- This is especially true when system with 3200 Mhz is Intel and 2nd system is Ryzen, since Ryzen chips are capricious with RAM speeds.