I recently bought the LG 27UD88-W 27" IPS UHD (Max resolution: 3840x2160) to pair with the Titan X (Maxwell) card in my MacPro (mid 2012). I am unable to set the max supported resolution. Latest web drivers for the Titan X. Checked with both Display Port & HDMI ports, same issue on both. The monitor is detected as UHD, but under "scaled" for display settings the max I get is 3360x1890 What could be the issue?