Well...
"To do this, the processor used the Machine Check Exception (MCE) feature of Pentium processors or the Machine Check Architecture (MCA) feature of some Pentium Pro processors." Why do i think this is virtually impossible because i m not running an Intel Pentium CPU?
I also checked those most common reasons. None of them seems to fit at least a bit.
-no OCing (TRIED to overclock my GPU a long time ago but reset it to default because it actually wroked slower - no other attempts of overclocking)
-more than enough power and stable (a 530 W
PSU - ASUS Probe showing a smooth voltage graph)
-no overheating, fans running at optimal levels (temperature alerts set in BIOS - ASUS showing safe temperature and optimal RPMs)
-memory modules untouched since the hardware upgrade (all worked normally since then)
Appreciate the help but it looks like this ain't gonna solve the problem.