Maybe it will be possible to unlock the Dell 28" 4k to do 60hz on displayport. The panel should be capable of supporting it, it might be a firmware restriction.

Maybe it will be possible to unlock the Dell 28" 4k to do 60hz on displayport. The panel should be capable of supporting it, it might be a firmware restriction. edit: Looks like the Dell 28" is a TN as well, that's unfortunate.