Question After major PC upgrade the PC boots, powers off after a few seconds, then boots into Windows normally without issue

Oct 24, 2020
Hello all,

I recently upgraded everything in my PC besides the SSD, power supply and GFX card (new motherboard, CPU, RAM etc). The issue described in the title did not start immediately, rather it started two days after I completed the build. Right now my PC boots but even before POST it powers off, powers back on after a few seconds and loads into Windows without any issues. I can then use the PC as normal. I ran a complete system stress test for about 20 minutes without problems.

What I have discovered is if I remove my graphics card from the system and use on-board graphics, the PC boots normally without shutting off. My card is a 1080Ti FTW3 edition with an EVGA Hybrid water cooler.

Here is what I have done to troubleshoot so far:
Replaced my UPS with a power strip.
Moved the graphics card to a different PCI-E slot.

I've only performed these two steps because I'm entirely unsure of what to do at this point. If this was an issue with power delivery, why can I boot into Windows, game for multiple hours and run stress tests without issues? I also used the 1080ti in my old build for two years without any issues.

Here is what I did prior to figuring out the 1080ti might be the issue:
Replaced my UPS with a power strip
Reseated RAM/placed in different slots
Replaced the power supply's 24-pin MB connector and 8-pin CPU connector (fully modular power supply)

Here are my specs:
ASUS Prime Z390-a
i9 9900k
Cooler Master MasterLiquid LC240E AIO CPU cooler
1080Ti FTW3 edition w/ EVGA Hybrid water cooler
Corsair Vengeance LPX 32GB DDR4 3200MHz
Corsair RM 850x 850watt power supply
Toshiba 250GB SSD (boot drive)
Samsung 970 EVO plus 1TB m.2 SSD

Thank you all for any advice :)