arestavo
A shut off/restart indicates that the power supply can't handle it, or the video card is being pushed too high (usually overclocking - I've actually had this happen on my 3090 FTW3).
 
Test in another computer (friends/repair shop), test a different power supply.
 
If you cannot do either, RMA the card. If the problems persist, RMA the power supply.

Well im going to assume its not a PSU issue, as im not overclocking. 650 is recommended for the 3080. Im above that. Ill see if I can wrestle my daughters PC away from her to test.

Viper97
Three things...
 
1. Always make sure you don't have a lot of misc. stuff that's not need. Like oh I don't know coupon savers in the background.
2. Get rid of stuff, get to cleaning out pop up blockers, underwear hiders etc.
3. Delete old drivers.
 
Okay 4. Stop complaining because your stuff is so full of stuff it causes conflicts. I've never had a problem with a new release of hardware because I keep my system free of junk.

Funny guy. Too bad you dont know what I actually do for a living.

Almost certainly your power supply. Age and make?

PSU’s age and they degrade by not being able to supply the burst loads they could when new.

What kind of power is being pulled by the card when in TimeSpy? Use CPU-Z to tell you.

WraithDecay

arestavo
A shut off/restart indicates that the power supply can't handle it, or the video card is being pushed too high (usually overclocking - I've actually had this happen on my 3090 FTW3).
 
Test in another computer (friends/repair shop), test a different power supply.
 
If you cannot do either, RMA the card. If the problems persist, RMA the power supply.

Well im going to assume its not a PSU issue, as im not overclocking. 650 is recommended for the 3080. Im above that. Ill see if I can wrestle my daughters PC away from her to test.

I thought a 750 was recommended for the 3080? (which you still have so not saying it is your psu)
That said i would look at your bios version, someone else earlier had a similar issue and that fixed it.
 
Edit: downclocking/undervolting it would rule out the psu anyway so that is a easy test.

WraithDecay

arestavo
A shut off/restart indicates that the power supply can't handle it, or the video card is being pushed too high (usually overclocking - I've actually had this happen on my 3090 FTW3).
 
Test in another computer (friends/repair shop), test a different power supply.
 
If you cannot do either, RMA the card. If the problems persist, RMA the power supply.

Well im going to assume its not a PSU issue, as im not overclocking. 650 is recommended for the 3080. Im above that. Ill see if I can wrestle my daughters PC away from her to test.

No, per Nvidia 750 watt PSU is the minimum recommended not 650. Depending on its age and how hard it has been stressed your 750 may not have the capacity with which it started. I would make sure if it's connected to an APC that the APC is rated for 800 watts plus. If you don't have an APC a 1000 watt APC which conditions your power would be a good long-term investment for this system and its replacement.
 
Some people have had success with 650 watt PSU but an i9 at high clock speed is nearly the worst case scenario for total system draw. The PSU market is so constrained right now I would try to buy an 850W or 1K W Gold or better PSU and sell yours used on Ebay. Someone will probably buy it.
 
If you're not willing to upgrade your PSU I would start by under volting your CPU, if that eliminates the problem your PSU can't take the load and I would RMA the PSU.

WraithDecay

arestavo
A shut off/restart indicates that the power supply can't handle it, or the video card is being pushed too high (usually overclocking - I've actually had this happen on my 3090 FTW3).
 
Test in another computer (friends/repair shop), test a different power supply.
 
If you cannot do either, RMA the card. If the problems persist, RMA the power supply.

Well im going to assume its not a PSU issue, as im not overclocking. 650 is recommended for the 3080. Im above that. Ill see if I can wrestle my daughters PC away from her to test.

How old is your power supply? Assuming is bad, especially if it's an old one. Just because it's rated for 750, doesn't mean it can still do that (power supplies age and can produce less over time)

PSU age can certainly be the problem here.

I would wager the PSU is the issue...tho spending more money on top of the FTW3 is annoying...especially since it's not guaranteed to fix the issue
 

If you have another PSU plug the GPU into it and run the system on the current PSU if it doesn't fail then your PSU isnt enough. 
 

I am having the same exact problem. I have a Seasonic Focus Gold 750w PSU with 3 PCIE cables plugged in. The moment I enter a game like FFXIV from loading screen, my entire computer shuts down. I do have a 9900k, but not sure if that combo is basically overloading the PSU. It's starting to sound like 750W is not enough for this GPU and you want to be at least 850 minimum.