I am sorry to hear you are having problems but let me help you.
As you mentioned before, the H processors can handle 3840x2160 at 60Hz. Also in the same quick reference for 4th generation processors it is mentioned that the U processors can handle 3200x2000 at 60Hz.
Our current drivers provide the possibility to reach this configuration but it is important to mention that single Link only is supported by our controllers. Our engineering department has been working to develop newer drivers including fixes and patches. It is probably the driver with this will come but at this point there is no ETA yet.
1) An Asus representative demonstrates, step by step, how to enable collage mode, 60Hz and at the same side get rid of glitches likes two taskbars in the below youtube video:
Have you tried this method? Although he says he tries that on an Intel Haswell GPU, he does not specifically mention which particular GPU model (HD 4400, HD 5000, etc) he tries on in the video. Therefore YMMV. Please let us know which specific card you have and whether the method demonstrated in the video works for you or not.
2) It seems Intel has recently released a new driver on 23 March 2014. The method demonstrated in that video may start working after installing the new driver:
Let us know your results.
Even extending the display would previously just lead to my machine crashing and rebooting (back when I made those posts).
With the latest official drivers, things have improved. Not only do I not have any driver crashes after coming back from display sleep, but I was able to activate extended mode from the getgo in both modes (previously it would either mess up the display, with one half only filling half the area, or the resolution being completely out of whack).
Long story short.. the computer started in clone mode, switching to the proper extended mode worked, as did creating a collage from the two displays.
And all that's on a Dell UP3214Q revision A00 (so no firmware fix for half screen issues and sleep issues). I'll drive this display in collage mode for a few days now seeing if there's anything that off.
I just tested the sleep/wake. And I'm afraid that's problematic.. I had to power cycle the screen to get the picture back. However, that also happens frequently with my U4500 based Brix and the U4300 based Elitebook 840G1 using the 15.33.18 drivers - display goes off (both on two Dell U3014s and an HP ZR30w) and it takes me playing a whole drum set on keyboard and mouse and sometimes a power cycle to get the picture back, pointing to a what is probably another driver issue.
Unfortunately, with an A01 revision display, things are back to not working again. Swapping clone/extended mode settings (change display order) has always been hit and miss (with the wrong config immediately crashing your entire box), and being unable to swap display order, my display now starts in the middle, instead of at the left.
Joining this conversation. I have a NUC with hd5000 graphics and an ASUS pq321 monitor. I realized I had been running it in 30hz since getting it.
Downloaded the newest Intel drivers offered by Windows Update and set up collage mode. In general works fine until I leave the machine for a while. I don't allow my machine to sleep, but it does turn the monitor off after a while. Once it does I can't get it to come back up with keyboard/mouse. I have to turn it off and back on. Once I do so and log back into Windows 8.1, all my open windows have shrunk down to a small size in the top left corner of the screen and there is a ghost taskbar in the middle top of area of the screen. Have to log off and back on for that to go away. Will try the latest drivers from Intel now.