My personal opinion,from 2 failed upgrades(with Intel 4000,black/blank screen on restart after upgrade),and now 3rd instal of 8.1(still have code 43/31),this time though no blank/black screen on restart from upgrade.I have sent support requests to intel & ms(both (without going into detail for fear of legal retribution)place the blame on each other & amd)only fix i have found so far is total clean instal of win 7),and i mean,TOTAL FULL CLEAN INSTAL.(mobo bios,etc....)
To me,8.1 is the culprit.
p.s.All o.c's were reset to standard before upgrades.
i5 3570k(@4.5)./ga-z77x-ud5h-wb./hyper T4./2 x 4gb vengeance 1600 c8./sapphire dualX 7970 3gb OC boost v2./1tb WD FAEX Black./lg bh10 blu-ray r.w../corsair hx850./antec df30./z506 spkrs./lg e2240v./win 8(8.1) pro x64 (oem disc)