It has two 8-pin PCIe power connectors, a slightly different power delivery and a custom triple-fan cooler. The maximum power limit of the GPU is 260W (versus 240W for the reference design), which results in higher clockspeeds.
Performance seems to be a tad below a fully overclocked reference card. The power consumption is about 9.1 percent higher than the reference card, but noise readings under load are 24.8 percent lower thanks to the better cooler.
More info and pics at VideoCardz. The ROG STRIX Radeon RX Vega 64 is expected to ship by mid-September;