LinusTechTips just tested this (video is not on YT yet though), and their benchmarks show that it's only really useful as a HDD cache. When used as a SSD cache

LinusTechTips just tested this (video is not on YT yet though), and their benchmarks show that it's only really useful as a HDD cache. When used as a SSD cache the only real difference can be found in synthetic benchmarks. It's unfortunate that it's only available for Kaby Lake, since I imagine that most people in need of a HDD cache run much older systems.