I'm still getting low hashrate on my Vega 56 with max settings of core 930 mem clock 900  and 840mv any thing higher than this the GPU will crash in hiveOS, my hashrate is 44mH and here is the tweak settings I use

amdmemtweak --cl 18 --ras 23 --rcdrd 22 --rcdwr 11 --rc 34 --rp 13 --rrds 3 --rrdl 4 --rtp 6 --faw 12 --cwl 7 --wtrs 4 --wtrl 4 --wr 11 --rfc 164 --REF 15000

The memory is hynix memory