To me it looks that the monitor is allright: I ran it under W7 , allright, scaling and font problems. Yestardy I installed W8.1 and the support from within the OS is allright . Monitor gave and is giving a clear picture, no flickering in 2D , but.. no 60Hz.
When I downscale the resolution to full HD or WHQD I can run 60 Hz no problem, but the ultimate resolution does not work at 60Hz.
AT Tomshardware one guy wrote that with a pair of 290s he had had the exactly same issue like me /us/ and bought a pair of 780s instead and BANG- 60 Hz out of the box.
The other wrott that replacing the 290 with 770 had solved the problem as well..
There is a hell of a lot of people complaining about signal loss and popping noise on different makes of monitor.
One thing in common - they all use the same panel.
That to me is a hardware flaw (IMO)