Disabled P2 state, but my memory only clocks to +425 for 4233Mhz. After that it becomes unstable. Hashrate still 30-31Mh/s.
Did you try to increase the power? Higher clocks need more power, or else the cards will trottle. Also make sure that the core clock don't drop. with 1800 core I get ~33.5 (MSI Aero 1070ti). I also use the kernel --oc 5
power limit is 65% and my core clock do not drop from 1900Mhz.