Hi and welcome to the Gigabyte Forum.
I think we have a slight problem with the language there and I am afraid I don't totally understand your post. However it does seem like the motherboard works ok with the smaller PSU but not the larger one. If that is correct then obviously the 500W is ok but the 850W is faulty.
right
...
850W PSU is 2 rail..2 suplly lines +-12V
500W PSU is 1 rail only 1 power line..
i dont know if that tensions on MOBO is good...nobody knows it
16.2V is brutal more by me....
but with both of PSU got it...
now continue stress test with prime95 on Gbit and working good,without restart or off
edit: friend called me ,that 850W PSU is good,energymeter looks good statistics tensions,ampers and etc. thing...so 850W is good..
where is bug?
RAM:memory86+ looks 0 errors.--