So after giving up on the 4k TV as a monitor I bought a pair of nice Lenovo monitors with really thin bezels expecting to make a nearly seamless span. But along the top and both sides I have 3/8" of unused display space. The slider in OS X does underscanning fine but is there no overscan possibility? The displays themselves have only 2 options - original aspect ration and full screen. Neither changes anything. I have 1 hooked up straight HDMI and the other DP-HDMI but they both look the same.