Question System shutting down then rebooting ?

[lottaphotos4]

OK. I'm putting this under System because I'm not 100% sure what the issue is, or what category it should go in.

Short version: When playing something graphics intensive (GPU near or at 100%) I occasionally have a problem where the computer goes from on and running the game to IMMEDIATELY off. No messages, no shut-down process. Just one moment I'm shooting zombies (7 Days to Die) or raiders (Fallout 4), and the next moment the computer is silent and off. At that point I count to five, and it reboots and acts like nothing is wrong.

Talked to somebody I know with some Geek Squad experience and he started talking PSU rails and GPU draw.
He's a smart guy. But he couldn't dumb it down to where I could figure out what the issue is, exactly, or what I might be able to do about it.

Is it something I have to change in how my GPU is wired?
Is it a switch in/on the PSU?
For that matter, is it a GPU or PSU hardware issue?
Or is it something else entirely?

My best guess, from what I'm seeing and what he's saying is that when the GPU gets an especially heavy workload, it's causing some sort of auto-fault shut off.
But is that a hardware shut off? Something that can be monitored (to verify) in Windows?

OK the hardware (built this in 2019, have run a couple thousand hours without any real known issues other than this)...

CPU: INTEL i7-8700K
GPU: Radeon RX Vega 64
PSU: Corsair HXI 750
MOBO: ASUS HERO X
RAM: CORSAIR 16GB (2x8GB)
CPU COOLER: CORSAIR H115
WINDOWS 10

I should note that I have Radeon Adrenaline running with GPU load and temperature as an overlay.
NOT running hot when this happens.
Temperature on GPU is consistently below 68C the way I have the temp curves set up.

So...what the heck is this?
I'd like to be able to verify the issue in some way, and fix it.

From what my friend said, it might have to do with the power cables from the GPU "sharing a rail"?
As far as I know the PSU is still set to factory settings.
(I do not have the data cable to the PSU connected. Ran out of internal USB ports and have not wanted to take things apart to add the Commander PRO yet.)

I guess the best answer would be "change the GPU connections from X to Y".
Second best would be "Make sure switch X on the PSU is in Y position".
After that I'm guessing we get to less fun choices like "You need a bigger PSU" (which I do not think is that case---GPU mostly runs without any issues at max/220W, and as I calculated when I built the computer, there SHOULD be about 100W of margin, even with full load and fans running).

Thank you for taking a moment to help me figure this out.

 

[Lutfij]

I would ask you to (source)borrow(, not buy) a PSU from a friend or neighbor who has a reliably built, branded PSU with at least 850W of power at the entire system's disposal. If you don't incur any anomalies as stated above, then the issue was with your existing PSU. Troubleshooting isn't exactly about pointing a finger and hoping the guess was right, you need to go through a process of elimination until you're left with a logical conclusion as to which hardware was the root of your issue, provided the issue is hardware and not software.

Apart from monitoring your GPU temps, did you monitor your CPU temps when under load?

 

[lottaphotos4]

Hey Lutfij, thanks for taking a moment to reply.
No issues with the CPU temps, the Corsair cooler has been amazing that way.

Your suggestion to borrow/not buy a PSU from a friend or neighbor is a good one...I just don't have anybody around that can do so. (Not a friendly neighborhood, and my only tech saavy friend is 1000 miles away.)

Again, thanks for taknig the time.
I'll keep you posted.

 

[lottaphotos4]

OK, here's a possible update to this issue.
It's also a question for anybody that's got experience with this:

This may be because I'm running my computer thru a UPS.

Just found out that the UPS is rated for 650w.
My PSU is 750w.

Most of the time, no problems that I can detect, everything runs fine.
Problems when GPU is at 100% during a game with lots going on.

So....my gut says this is the issue.
Want to know what you think.

Thank you.

 

[lottaphotos4]

Update on this issue:

I was able to confirm that my system is drawing (max) about 480w under heavy graphics load, so the UPS should NOT be an issue.

Been reading through things, and the Question now seems to be (with my Vega 64 GPU)...I'm currently running it connected off the 2x 6+2 power cable (splitter) from the 750w PSU.
Seeing various comments/opinions on whether or not I should go to two entirely seperate 6+2 cables, as opposed to the one "split" cable.

Any thoughts on that?

Would follow up with a question on my PSU (Corsair 750HXi)....I know it has the capability for single or double rail configurations.
I'm using it as delivered,...not sure which of the two configs it's in, but with respect to how to connect if I use two cables....One rail? Two? Any particular PCIe ports in the PSU to plug into (there are four, but don't know how they're related to the "rails")?

Thank you