Forgive me if I’m not posting this in the correct area. I just got my ftw3 ultra 3080 today and installed it. Did the ddu and fresh driver install and everything. 3 separate pcie cables from an evga 850 GA psu. Did port royal and fire strike and getting above average scores and temps are really good. Games like warzone, halo, gears 5, iracing all worked well so far. Load up shadow of the tomb raider to run its benchmark and while adjusting the settings before I even run the benchmark the pc just completely shuts off like someone flipped the power switch. Reboot and try again and does it again. I’m just really concerned about what on earth could be causing this…anyone have ideas?

Is this a brand new GA, or one that you've had for awhile?
 
EVGA had an issue with the GA line of PSUs with the higher end 30 series cards and rebooting under load. Contact EVGA and see about getting your GA RMA'd for a fixed version: https://www.evga.com/about/contactus/ 

Bad power supply.

I had a similar problem with my 3090 and a Seasonic 850W Titanium - replacing with a DPP12 1500W fixed the issue. If you undervolt your card and the reboots stop, you have your answer.

ty_ger07
Bad power supply.

+1

it's definitely your PSU. i had a 1000w GQ powering a Strix 3080 last year and the system would reboot randomly during gaming. switched to a 1200w and the problem stopped

sounds like hardware!

Seems like after reading responses and checking some Reddit posts that the most likely issue is power spikes in certain games causing the power supply to completely shut down. When I get home I’m gonna check swapping off eco mode and check power draw. I use hwinfo64 so hopefully that reads power draw. Be my first time trying to diagnose a psu. It’s an EVGA 850 GA model and others have stated they had shut downs as well. I could RMA but I’ve never done that and not sure of the process. Would definitely want as little downtime as possible.

pzvzhz
what is your cpu\mobo?
had 3 random shutdowns with 3090 ftw3 ultra with my new 11900k\z590 apex xiii
one was in cp2077 at 4k
one was in pubg at fhd
never happened on my old 8700k\z370 with same gpu and psu.
maybe it's because of the raw BIOS and we have to wait for stable versions.
 

Ryzen 7 5800X on a Strix X570-E

If I RMA this 850 ga psu will I have to ship cables as well? I’d love to just unhook the cables and swap in another psu…

Gotspeed_2000

dervin3
If I RMA this 850 ga psu will I have to ship cables as well? I’d love to just unhook the cables and swap in another psu…

If you are going to RMA the psu I would email the customer service and get a written response.  The last thing you want is for them to deny your rma after you mailed in your psu and then have to go through the hassles of trying to get it sorted after the fact.  Get it from EVGA, not the forum and do it in writing in case anything goes wrong.  

I was just asking about the RMA process in which I would do directly through evga. Was just curious if you RMA a modular power supply do you have to send in the cables as well.

It's usually better to have some headroom in your power supply. Get more than you need. Could solve this problem.

maybe a bad psu

dervin3 did you ever get a definitive answer on which component was the issue video card/PSU/mobo?

Adding my 2 cents here.  Purchased the 850 GA last October to make room for my new 3080.  Experienced the same issues with the PC randomly shutting down.  I called and spoke to their customer service rep and he immediately stopped me when I said it was a GA and offered a replacement, saying that PSU was an issue.  They sent me a brand new 1000w G3 in exchange.  
 
Here's a thread with more info: SuperNOVA 850 GA 850 / 3080 FTW U? - EVGA Forums