The main thing about this driver is the enhanced CF profiles for the Radeon Pro Duo, but it does offer more than what the release notes say.
AMD were nice enough to give us this driver early saying little more than that it contained new DirectX 12 optimizations, so we spent a lot of time testing it and low and behold we got a performance gain in every DirectX 12 game we tried.
While the performance gains are not massive, around 3-5% in most cases, they are very welcome. We expect that AMD are working on more optimizations for future releases, they want the best DX12 performance for when then next generation of products release.