As to the 1st part. Yes, CCC is not explained well. Try to uncheck "Reduce DVI Frequency on high-resolution displays." And then uncheck "Alternate DVI operational mode." And if you do not have black borders around edges of screen with Disabled GPU up-scalling in that menu, I would keep it disabled. For the 2nd part: I had no problem to right click desktop which displays context menu and then pressing <Prt Scr> key on keyboard and pasting this menu to mspaint. - You are probably only person with this corruption issue, but others had even problems to set full 2560x1600 resolution for some DisplayPort cable was not detected and so on. (not an problem free monitor) - your "pixel clock: 268.5mhz" tells you this: 2560 * 1600 * 60Hz = 245,760,000Hz = 245.76MHz minimum frequency used. Then there are pixels around which are not displayed and some other stuff transmitted which gets in total to 268.5MHz. (Given frequency tells you what kind payload goes via cable.) 1920x1080@120Hz requires bit more data, so cable should not be an issue, even average DVI can get it done without corruption.