I had that problem with both Windows and OS X over Displayport. On Windows 7, windows would resize to a tiny 640x480. On Windows 10, windows would resize to something larger like 1024x768. Tried the Windows registry hack in both Windows 7 and 10 but it didn't do anything. I ended up...
To answer my own question, I got a Geforce 970, and now the display runs at 60Hz, didn't have to do anything but plug it in. Works great, no flickering or other problems using a cheap 6ft DP-DP cable from Amazon.
I just got this display, running with a 650 Ti BOOST (I don't game at all). Default resolution is 4096x2160 50Hz, works fine but is a little jittery at 50Hz. I tried creating custom resolutions, but Nvidia Control Panel only lets me set up to 57Hz. I can try to create a 60Hz setting, it will...
I registered just to reply to this. My new e6600 needs 1.4V to run stable at 3GHz. It needs 1.525V to run stable at 3.2GHz (355 FSB). I spent all of today messing around with settings on my P5B Deluxe but can't do any better, and I thought I got the crappiest e6600 ever.