maybe different brands get different results

I have 6 asus strix 390 oc in one rig and had to play with core oc while reducing voltage to get near that value

Not every card is the same, I fine tune each card with different oc and voltage because some won't produce more h/s past certain setting so there's no need to keep stressing the card, some get there with only 1120-1130 others only with 1150 core clock.

drivers also have influence and you need to check wich is best for your rig