PC Perspective article here.
The current state of CrossFire for Vega isn’t amazing me. Scaling at 2560x1440 is abysmal with only The Witcher 3 going above 20% improvement by adding the second card. At 4K we do see a better result, ranging from 54% to 84% depending on the game. Hitman in DX12 was the outlier though, with zero scaling, indicative of the continued concerns over the new API and the pressure it puts on developers going forward.
With two Radeon Vega Frontier Edition cards in CrossFire, AMD is having trouble keeping pace with a single GeForce GTX 1080 Ti.