I won't bore you all with too many details, but here are the basics: MacBook Pro 11,5 (high end 15" with two graphics cards) LG 27UD68 UHD Monitor with a maximum resolution of 3840 x 2160 @ 60hz. I've tried this setup using a HDMI 2.0 cable (high speed/4K rated). No dice. Went to Best Buy and got this: http://bit.ly/2e2oKYi I am able to run at the higher resolution, but a lower refresh rate (30hz). Likewise I'm able to run it at 1080P at 60hz. But I want the "best of both worlds" and what I know this monitor is capable of - 3840 x 2160 @ 60hz. So...what do I need to do to get this to work here? I'd like to avoid any third party apps like SwitchResX or anything like that, but if that's what it comes to then I'll do it. I have to imagine that it's something I've done wrong or am not doing. Any help would be appreciated.