I've been doing a lot of research recently and I've found the new $800 RX VEGA can do up to 41 MH/s @ 300W.
Whoever the AMD CEO is she needs to stripped naked, tied to a post and publically caned with one lash for every MH/s under 80 MH/s and one lash for every Watt over 200W.
First it was not amd claims, second from badwitch calculation vega is capable do 80 MH/s and i think big mining farms have optimized miner (cause vega was sold out in first days even if is poor in gaming) , I think Claymore have asm for vega but just deley it for big mining farms sake ... It is business...
They're a big enough company they should make proper drivers for Linux and Windows, this crappy mining performance is probably mirrored with crappy gaming performance.
Also, what about the 300W? My HD 7990 uses 300W and gets 55 MH/s (MUSIC,EXP,UBQ) and the RX VEGA is doing 41 MH/s with the same power consumption OMGWTFBBQ.