May be an optimization issue

On Tuesday, AMD unveiled Radeon RX 480, the first graphics card in its tenth-generation Radeon lineup, based on 14nm FinFET Polaris architecture, and already some critics have claimed that some aspects of the benchmark are not giving an accurate presentation of CrossFireX performance when tested against Nvidia's high-end Geforce GTX 1080.

And Nvidia VXAO technology

Rise of the Tomb Raider has received a new patch which brings both DirectX 12 support, Nvidia's VXAO Ambient Occlusion technology and some other optimization, fixes and tweaks.

To implement asynchronous compute engines

AMD has partnered up with IO Interactive and its upcoming Hitman game which will be the newest member of the AMD Gaming Evolved program and feature performance optimizations as well as unique DirectX 12 hardware features.