should be 54.9mhs 1100/1026@787mv @ 112watts ...
Can you please explain how do you go below 800 mV?

with linux and atitool
Which miner, what memtweak settings?
I have 6xVega 56 sapphire REF. 56 bios, and max. is 50mhs. No run above 1070cc and /1027mc/mem 820v.
My Vega56 is on :
1090 core
1020 mem
0.812 v
Gets me 53.19mhs on mmpos non modded bios.
it seems that mmpos uses amdmemtweak timings by default ))
yes all that built right in

Where you set the smart tune(low,mid,high)?
Miner is Teamredminer?
Miner is TeamRedMiner
Smart Tune to Custom
ras = 26 / rcdrd = 12 / rcdwr = 12 / rc = 38 / rp = 12 / rrds = 3 / rrdl = 5 / rtp = 6 / faw = 12 / cwl = 8 / wtrs = 4 / wtrl = 9 / wr = 13 / ref = 21100 / rfc = 239
This is on a Hynix Rev 1 MSI Blower.
Hope it helps ya.