Remove the overclock on the freesync monitor and retest. I would also suggest changing to a different power supply if possible (much higher wattage). Otherwise, it could be a hardware problem but in my experience with testing Vega 64, it really needs a high wattage power supply for max stability. Previously when I testing with both a 850w Corsair and a 1000w Seasonic power supply. The computer would randomly restart or it would shut off completely due to over current protection on the power supply. This was tested on two different computers using Vega 64 with FFXV opening fire scene. The computer would shut off completely as if there was a power outage. It can also randomly reboot while playing a game or idling.
There is a discussion about Vega's transient power spikes while gaming over at Seasonic Prime triggered by sudden power increases - jonnyGURU Forums
There the issue is more about the Seasonic PRIME 1000w not being able to handle the transient spikes from Vega 64 but different power supplies might handle the situation differently, so your issue might be related.
In my case I fixed the issue by upgrading to a Corsair HX1200 watt power supply.
Tested without freesync "overclock" but same results..
It's seems more in the temps then PSU..
I mean why 750W wont be enough?
Still..I will indeed check on my other PC..
How I was using for 6 month the Vega 64 with no issue till it died,
And why this new vega which only in use for 2 month starting probably to die also..
What is wrong there ;/
Uhmm,I really hope it's just the power supply and not the GPU it self..
Will test it tommorow and update,
If you don't have another power supply to test preferably a 1000w or 1200w, then you can lower the the power limit by 30 or 50% and see how it runs then.
Just made a retest using my other computer powersupply (It was connected only to the vega when the other powersupply where for the system..)
Tested again and no crash,
Was thinking that it's indeed the powersupply..
Tested again with my own powersupply to see it crashing again to double confirm it's the powersupply and it didnt crash..
Which made me thinking again what's the difference (The test was on my other computer monitor)..
So is it really the monitor fault?
Returned the computer back to it's MG279Q Monitor and discovered that I never really disabled the freesync "overclock" even that I thought I did..
Had to use CRU Reset function..
Went again to benchmark and no crash!
So it's indeed was due to the famous MG279 Freesync "overclock" and not due to PSU/GPU..
Weird that everyone who is using that overclock never encoutered my issue but well..At least it's now fixed!
Thanks for the help!
Hope anyone who encouter the same issue to see this thread