Prior to the updated Dual-Mode Standard release, Dual-Mode cable adaptors were limited to a TMDS clock rate of 165MHz providing support for display resolutions up to 1080p with 60Hz and 24 bits color.
It's also possible that Canonical will release early builds of the dual OS for us to try -- just like it's going to cater for experimental GNex owners next month.
This release supports the next generation of Dual-Mode DisplayPort enabled personal computers and Dual-Mode DisplayPort cable adaptors, expected to be available to consumers later this year.