I am quite sure my monitor, a Dell 4k P2715Q, will do 60hz. Holding the Option Key and clicking "scaled" does nothing. Thank much, I am thinking I may need a different cable? I have a nice HDMI cable.
Yep, HDMI 2.0 has to be enabled manually.
If your monitor was built before the cut-off date mentioned in the article it’s limited to HDMI 1.4 (30 Hz) though. (If you have an Intel Mac you can get 38 or 39 Hz using custom timings in this case.)
Well, no rest for the wicked. I have horrible flickering where it just goes blank for a few seconds every minute or so. Ouch. I have ordered a USB-C to Display port cable.