Question: My monitor and DisplayPort cable supports DP1.2. However, the AMD VGA driver still shows "A display capable of DisplayPort v1.2 data rates and multi-streaming is currently connected to a connector that does not support DisplayPort v1.2" on AMD FM2+ platform. How to fix this issue?(6/1/2015) Answer: Please download and install AMD VGA driver v14.9 to solve this issue.
AMD VGA driver V14.9 download link: http://support.amd.com/en-us/download/desktop/previous/detail?os=Windows%207%20-%2064&rev=14.9