OK, probably a stupid question here, but I got a LG 27UD68 monitor to go along with my 2016 MBP (no touch bar version). Got it hooked up, but it's displaying at 30hz and it's a bit choppy. It's connected via the USB-C adapter and a high speed HDMI cable. I can't seem to get the option to change the refresh rate in Display. Any ideas? I have to assume that this is possible via standard OS X controls and I won't need a third party app to make this work.