What motheboard do you have? Try again 6% on ACC from what i know it is the seting which bring the best stability..
Try with HTT LINK at 1800(instead of 2000) and NB frecuency at 1800 to, just lower the multiplier of them..i thinking at first Deneb 920& 940 which have a little lower HTT and NB(1800) frecuency... may be that two cores can do much-2000
And may be try out different bioses for you MB may be there's one which brings more stability..