http://wccftech.com/amds-rx-vega-64-etherium-mining-248-watts-of-power-draw/

There are quite a few reports circling around the internet today regarding disruptive power efficiency claims of the Vega 64. So we decided to put this theory to the test by taking a watt meter and a trusty Vega 64 (liquid cooled edition) and running em through the paces. The test was conducted by our US Editor, Keith May and the liquid cooled Vega 64 provided to him by AMD.

Since software isn’t usually a reliable tool to measure power draw, we used a Kill A Watt meter to test the power draw from the wall. The reports we have been hearing claim a mining power efficiency of 43.5 mHash/s on 130 Watts for ETC. This is a hashing power efficiency of 0.33 mHash per watt. Considering that other publications have only managed to get a hash power efficiency of 0.13 mHash per watt (before the mining driver update) and the GTX 1070 has a rate of 0.18, this is quite the claim to make. In fact, if this claim is to be believed than the Vega 64 just jumped in efficiency by around 253% since launch day.