To ensure compatibility and optimal experience with AMD Eyefinity technology, it is recommended that only AMD Eyefinity technology validated dongles be used. A brief description of DisplayPort dongle types is provided below. For a list of validated dongles, see http://support.amd.com/us/eyefinity/Pages/eyefinity-dongles.aspx.
Active dongles
use DisplayPort signaling to actively translate and re-transmit signals from a DisplayPort [...]