AMD certified its Radeon Adrenalin 18.9.3 drivers from Microsoft, received WHQL certification, and released them with that certification because they were previously listed as BETA because they didn’t have certification yet.
Let’s remember that AMD releases WHQL drivers about every three months. Meanwhile, it provides BETA updates throughout the course to optimize for games that are released in between.
This latest version was specifically optimized for Assassin’s Creed Oddyssey and Forza Horizon 4, but also includes all other optimizations since the last WHQL version. In this way, if you have not updated to the BETA intermediate versions, you can see improvements in several titles.
The 18.9.3 WHQL drivers are available for Windows 7, Windows 8.1, and Windows 10 in 32-bit and 64-bit versions. You can download them from the AMD page or from your graphics card manufacturer.