So, after going crazy with this I did my tests on my daily use:
for exemple, today I turned on my PC, run R6Siege and run its built-in Benchmark, almost instantly I got a crash, game closes, gpu driver reset, HWiNFO showed 1770Mhz on core clock (P7 set to 1727 - 1168mv | PL 24%). So I re-load...