Try with 2 sticks of ram both from same set shouldn't really mix memoryI have a wierd similar if not the same issue. Just upgraded from a Ryzen+ 3200g to the 5800x on an Asus X570 Tuf Gaming board.
I have 32GB DDR4 RAM comprised of 2x 8gb Corsair Vengence and 2 x 8gb Crucial Ballistix both sets supposedly 3200 speed. When the previous chip was in I could only get the speed to 2666, which i thought may have been a limitation of the CPU. When I tried to set the speed higher the computer would not boot and after a few tries would go back to the BIOS setup screen.
However, when installing the 5800x and trying to increase the memory speed, it just wont boot and the fans kick in really high. I have to remove the CMOS battery to reset the bios....which is a real pain in the ass as I have to remove the Graphics Card to get at the battery!
Chieftec 850w I've tried with 2 sticks alsoOp what psu you using could be the problem with the crashes if not powerful enough
I don't know much about that psu to be honest but think that could be part of problem mate just had a quick Google and it's only got 2 year warranty do you know any one that can lend you another power supply there's been quite a few people with cheaper psu's haveing system crashes with the new graphic cards also the 5700xt gpu might be the rail isn't stable the best advice I was ever given on these forums was never skimp on your psuChieftec 850w I've tried with 2 sticks also
Right the memory I take it it 4 sticks of 8 gigDone a few stress tests and no crashing.
Looks like that psu was rubbish.