I just got done with a bit of testing on my Radeon VII. I can confirm XMR V7 & V8 can be pushed to 2700-2800h/s (can be pushed near 3k if you have a well binned card that can undervolt better than mines) using SRBMiner. ETH my card can hit 93Mh/s. So far this card is very meh for mining. I would still go with vega 56s for cryptonight and polaris cards for ETH.
Are you talking about a stock Vega 56, or one modded to a 64?
I dont know, im tempted to buy one. Blower style Vega 56 and 64 have bad coolers. Solder just melts then aluminium fins separates from copper base and throthling starts, or rig starts crashing. It is just the meter of time, it took about 6 months and 4 of my Vegas started to suffer from this. In Overdriventtool max temp was set to 65c and fan to 4900rpm and it still happend. So i took bad coolers off and put aio watercooler 120mm on few and arctic cooling air base cooler with 3 fans on one and temps are better then original, cards mining at least 6 months like that. Last one has gone bad few days ago so now im looking 240mm watercooler now for that caouse hot days are comming within few months and i want to test bigger aio

If Vega VII has better cooling solution, and it looks like it have then it is better card because of hasle of replacing the cooler, or rma-ing the card back in Germany in my case, bonus Vega VII hashes more and for same hashrate using 3 times less space if you compare it to 580rx because of tripple hashrate in eth