Question Reboots when playing some games, no BSOD

[HelloMrMinkle]

Hey everyone! My PC is about 2yrs old and has been running perfectly fine until a couple months ago. It has been rebooting on its own while playing some games. There are no signs that it is about to happen, just cuts out and about a second or so later starts back up (restart option in BIOS is not on, btw). The monitor does not shut off with the computer because i've watched the light stay on and the splash logo does not come up. The monitor and PC are the only things plugged into my strip (APC Surge arrest, green indicator light is fine) and the strip is the only thing plugged into my outlet. No other programs are running in the background (I do have the windows game mode enabled, though), other than monitoring software like HWinfo64, and that was only after I started having the problem a few times. Event viewer does not show anything except the Event ID 41(?) Kernel-Power after the system starts back up. I have some logs from HWinfo64 but I am not exactly sure what I am looking for and was wondering if anyone could help? The 3,5,12 voltages look fine, the temps for the cpu and gpu look fine according to everything that I've looked up before posting this. I did a 3DMark Time spy stress test and it passed with a 99%, but shutdown with the Firemark stress test last night. I've read that it could be the PSU but was wondering if there was anything I could try without purchasing a new PSU first? I don't want to purchase a new one and find out that that wasn't the issue and have a second PSU i'm not using. I do not have a friend who I can borrow a PSU or GPU from. I don't normally post so I am unsure how to attach my HWinfo logs. I'm just wondering if there are any setting with AMD Radeon or within game that I could try before replacing parts? I would greatly appreciate any help.

My specs:
MOBO - Gigabyte B150N Phoenix-Wifi
Processor - i5-6500, 3.2Ghz, 6MB
CPU fan - Cryorig C7
RAM - Crucial Ballistix 16GB, 2 -8GB DDR4 - 2400
SSD#1 - Intel SSD6 M.2 80mm, PCIe 3.0x4 - OS and programs mostly on this drive
SSD#2 - Samsung 850EVO 500GB - media
GPU - XFX GTR Black edition RX480 8GB GDDR5
PSU - EVGA Supernova 550G2 80+ Gold - I do have a warranty for the PSU but how would I prove that the PSU is faulty in order to sent it back and get a replacement?
Case - Phanteks Enthoo Evolv itx with 200mm front fan installed
Case fan - 140mm fan installed at back of case facing out - Cougar vortexHDB 1200/700rpm
Monitor - ASUS VG245 75hz Freesync monitor (I have freesync on but sometimes games won't use it and switch the monitor to regular 1920x1080)

As for the games that have been causing this recently: This first happened while playing Dark Souls 3. I was probably about 30-40 hours into the game before it ever happened, everything ran fine at 60fps, med/high settings(didn't use default, looked up suggestions for optimizing graphics settings to not use what wasn't necessary) System always remained pretty quiet while playing, fans never ramped up or got too loud.
I also started playing Witcher 3 again recently and it started happening. Medium settings for this game. I will note that I had played 140hrs of this game previously, sometimes for many hours a day, with zero problems. I have noticed in Radeon General Wattman that GPU usage jumps around instead of staying at 100% while playing.
It has also happened with Obduction.
I have always run the GPU stock and all default settings in AMD Radeon, which is also up to date.
This issue does not happen any other time the computer is in use or for any indie games that I play.

Other observations, not sure if they matter or help:
I looked for BIOS updates but there doesn't seem to be anything significant after my current version (F2).
Alt-tabbing out of Dark Souls 3 and back usually caused the menu to freeze when i would finally exit the game to desktop. Only game that ever did this. Is it a problem alt-tabbing out of a game that is not running at 75hz back to the desktop that is and then back again?
Also noticed that when I start DS3 there is a short beep on a white screen when the game starts, this also happened with Witcher 3 last night for the very first time.
I've noticed that the Windows taskbar transparency is not consistent with transparency effects turned on. Sometimes the transparency effect is just a little opaque and other times (like after the reboot) it will actually be somewhat transparent.
Currently have AMD Virtual Super Resolution disabled - should this be on?

Anyways, I apologize for the wall of text but I just wanted to include everything that I could think of in the initial post. Thanks for reading. Happy Tuesday!

 

[Eximo]

By default blue screens are automatic reboots.

https://www.tenforums.com/tutorials/69012-enable-disable-bsod-automatic-restart-windows-10-a.html

Kernel Power is usually just unexpected restart.

Super Resolution is when you render the game at a higher resolution and then downscale to fit your monitor. Typically, no, you would leave this off unless you wanted to try and make a lighter title look a little better.

You mentioned BIOS updates, what about the motherboard drivers themselves?

You mentioned CPU temperatures and GPU temperatures. What were they?

Witcher III sounds like you are CPU bound and the GPU has some idle time.

Have you looked into running Memtest x86? Could have some faulty memory, maybe just need to give it a little more voltage to get it stable again.

 

[HelloMrMinkle]

Ok, I do have auto restart checked under system failure option.
I did run one pass of Memtest86 last night and got 100%.
For the motherboard drivers what exactly am I looking for? on the Gigabyte site for my motherboard there is an option for BIOS drivers and other stuff, but not just motherboard drivers. Chipset? Sorry if this is a stupid question, haha.

As far as temps go, there are a lot in the HWinfo logs and I am unsure of which ones to give. What is the preferred way to share files on these forums?

 

[HelloMrMinkle]

A few temps when Witcher 3 cut out last night:
PCH Temperature - 48.5c- 58c
System - 50c
PCH - 54c
CPU - 54c
These all started in 40c or so and went up over the course of ~10min before the shutdown

GPU Thermal diode - started at 43c went up to 70c max over course of same time
GPU VRM temp1 - 43c-69c
GPU VRM temp 2 - 26c the entire time, no changes
fan at 2162rpm
-------------------------------------------------------------------------------
During the Firestrike test, which also lasted ~10min:
PCH Temperature - 51.5c - 60c
System - 42c - 54c
PCH - 48c - 57c
CPU - 39c - 51c

GPU Thermal diode - 54c - 85c
GPU VRM temp1 - 53c-84c
GPU VRM temp 2 - 26c the entire time, no changes
fan maxed at 2202rpm
-------------------------------------------------------------------------------
These are the same for both instances:

3.3V was consistent at 3.245
12V jumped from 12.024 - 12.168, 12.024 at shutdown
5V was consistent at 4.95
No thermal events
IA: Max turbo limit - YES
IA: Turbo Attenuation (MCT) - YES

Would core temps or core package temps be better?
I will note that even though both of these instances were about 10min long there has not been a consistent amount of time that games will run before they shutdown. sometimes an hour or so, sometimes after a 10 or so minutes, never right away.

 

[Eximo]

Core temps are more or less all we care about.

You do have one suspiciously cool VRM though. 26C is hardly above room temperature, not sure I trust that value. There are certainly some light duty VRMs on a GPU though, but I would still expect them to absorb some heat from the surrounding components.

Are you also monitoring your disk temperatures? SSDs can heat up as well. Fire up CrystalDisk Info and see if anything odd is reported there.

 

[HelloMrMinkle]

Ok, I will post core temps from those same logs a little later. Would the SSD temps from HWinfo log be sufficient as well?

 

[Eximo]

Maybe, it is just a thought. I know NVMe drives are known to heat up and throttle themselves. Shouldn't lead to crashing, but you never know. Would just be another data point to look at.

 

[HelloMrMinkle]

Ok, so I guess HWinfo was not logging SSD temps so I'll check them later and let you know. Before I downloaded HWinfo i had used another program that showed those temps (HW monitor?) and I don't recall them ever being that high, especially the EVO.

Core temps:
Witcher 3 instance from earlier post
Core 0 - 32-53
Core 1 - 32-56
Core 2 - 30-48
Core 3 - 31-52
CPU package - 32-56
Core max - 35-56

Firemark test instance
Core 0 - 36-50
Core 1 - 37-50
Core 2 - 33-46
Core 3 - 35-46
CPU package - 39-52
Core max - 37-52

 

[HelloMrMinkle]

I appreciate you helping me Eximo. So this evening I ended up taking the GPU out and dusting it even though there was very little dust that I could see on it. Did the same with the PSU and there was very little dust on it, as well. I started up Witcher 3 afterward and played for about 30 min with no real problems other than a couple ~ -5fps dips. HWinfo shows the temps were about the same as the instance previously posted.
SSD temps: 39c max for EVO, and 49c max for the m.2 stick. this was during gameplay

I might purchase a new PSU tomorrow in case the problem keeps happening. I read a lot of posts with a lot of different suggestions for what to try but I really don't want to keep trying one small thing after the other and putting the computer through these reboots over and over. It seems that most people think the problem would be PSU so maybe that's the best thing to switch out first. Would I be correct in assuming that?

Thanks again, I do appreciate your responses.