Starting with AMD Catalyst 14.6 Beta, AMD will no longer support Windows 8.0 (and the WDDM 1.2 driver)
Users should upgrade (for Free) to Windows 8.1 to take advantage of the new features found in the AMD Catalyst 14.6 Beta
AMD Catalyst 14.4 will remain available for users who wish to remain on Windows 8
A future AMD Catalyst release will allow for the WDDM 1.1 (Windows 7 driver) to be installed under Windows 8.0 for those users unable to upgrade to Windows 8.1

Feature Highlights of The AMD Catalyst 14.6 Beta Driver for Windows

Performance improvements
Watch Dogs performance improvements
AMD Radeon R9 290X - 1920x1080 4x MSAA – improves up to 25%
AMD Radeon R9290X - 2560x1600 4x MSAA – improves up to 28%
AMD Radeon R9290X CrossFire configuration (3840x2160 Ultra settings, MSAA = 4X) - 92% scaling
Murdered Soul Suspect performance improvements
AMD Radeon R9 290X – 2560x1600 4x MSAA – improves up to 16%
AMD Radeon R9290X CrossFire configuration (3840x2160 Ultra settings, MSAA = 4X) - 93% scaling
AMD Eyefinity enhancements:
Mixed Resolution Support
A new architecture providing brand new capabilities
Display groups can be created with monitors of different resolution (including difference sizes and shapes)
Users have a choice of how surface is created over the display group
Fill – legacy mode, best for identical monitors
Fit – create the Eyefinity surface using best available rectangular area with attached displays.
Expand – create a virtual Eyefinity surface using desktops as viewports onto the surface.
Eyefinity Display Alignment
Enables control over alignment between adjacent monitors
One-Click Setup
Driver detects layout of extended desktops
Can create Eyefinity display group using this layout in one click!
New user controls for video color and display settings
Greater control over Video Color Management:
Controls have been expanded from a single slider for controlling Boost and Hue to per color axis
Color depth control for Digital Flat Panels (available on supported HDMI and DP displays)
Allows users to select different color depths per resolution and display
AMD Mantle enhancements
Mantle now supports AMD Mobile products with Enduro technology
Battlefield 4: AMD Radeon HD 8970M (1366x768; high settings) – 21% gain
Thief: AMD Radeon HD 8970M (1920x1080; high settings) – 14% gain
Star Swarm: AMD Radeon HD 8970M (1920x1080; medium settings) – 274% gain
Enables support for Multi-GPU configurations with Thief (requires the latest Thief update)
AMD AM1 JPEG decoding acceleration
JPEG decoding acceleration was first enabled on the A10 APU Series in AMD Catalyst 14.1 beta, and has now been extended to the AMD AM1 Platform
Provides fast JPEG decompression
Provides Power Efficiency for JPEG decompression