The AMD Catalyst™ Windows® 8.1 Preview Driver can be downloaded from the following link: hxxp://support.amd.com/us/kbarticles/Pages/AMDCatalystWIN8-1PreviewDriver.aspx Support for new Windows 8.1 features, including: Wireless Display – Microsoft’s support for Wireless Display Technology 48 Hz Dynamic Refresh rates for Video Playback Aggressive V-sync interrupt optimization Skype/Lync video conferencing acceleration New DX11.1 feature – Tiled Resources
That is because you have a legacy GPU. Also note, no Radeon HD 4xxx series card is listed as supported on that site...