- updated all the firmware to the latest (thunderbolt has a separate firmware)
- bumblebee automatically disables the nvidia gpu on startup (i don't need the extra power or power draw)
I run in 1080p on the 4k screen, which is kind of sad, but the hidpi support just isn't there yet. Gnome3+ might have better support but can't replace the WM for xmonad in those variants.
But with 2+ screens available I'd think at least for me the usefulness would diminish, even if you'd have per monitor scrolling