I just buy this setup last week and it work perfectly well at 3840 x 2160 @ 60 Hz with Debian Jessie and the last fglrx-14.20 driver. The monitor is packed with a DP cable (and a HDMI cable by the way) so it worked out of the box with a FM2A88X Extreme6+ motherboard. I have see 30 Hz display before, but sorry, I can't enjoy them to test 1080p60 applications in a window while having code and debug around others windows.
Electronics schematic and hardware routing is a pleasure on UDH monitor, as coding side by side to the full documentations and output results. On the fun side, Google Earth is probably the most impressive with so much details that it's a bit like an immersion. The APU is still capable by itself to yield a few frames per second in full screen mode. Really need a powerful GPU if you expect more...
The monitor have a little bug in the power management that require to cycle his power to sometime weak it up, but this is a minor issue for me.