Got my new AMD RX Vega 56 today (Sapphire reference model).
It's wierd - to get it to get anywhere NEAR the officially rated 1590 "boost" clock, you have to kick the power limit WAY up (+50% in Afterburner) and UNDERVOLT the thing a lot (-100mv or so) in Afterburner.
Doesn't run very hot even so - I've yet to see it hit 70C while pushing DNet blocks with the fan around 70% - but have go to extremes to even get it past 1450 Mhz core.
 
 It DOES get over 9 gigakeys/sec though with some undervolt and some TDP bump (-100 and +20% seems to be about the magic point), so for the cost it's a much better cruncher than anything NVidia abet it soaks almost as much power as a GTX 1080ti to get to 90% of the keyrate (most 1080ti can get to 10 GKeys/sec with at most a little OC on the core).
 
 At stock setttings, it doesn't manage quite 8 GKeys/sec - which WILL blow away the GTX 1080, but again using somewhat more power to do so.
 
 I figure this one card would be good for well over 1 million RAC even at stock settings, perhaps 1.3-1.4ish if pushed.
 
 Given that the air-cooled Vega 64 is widely reported to clock higher than the 56, and it has 1/8 more cores, it seems like AMD probably has taken back the performance crown in ONE thing with Vega - though not by much.
 
 Gonna be interesting if AMD comes up with a "duo Nano" type Vega card, like the Fury Pro....