Horizon with T4 Resolution limited

I am deploying a new Horizon environment currently on Horizon 7.9 with ESXi 6.7 U2
the NVDIDA T4 cards are functional but we are limited to 2560 x 1600 screen resolution.

I have the profile set to grid_t4-1b, with one display this should be able to do 3840×2160 upto 5120×2880.

how do you enable the higher resolution options? hi high resolution screens such as a Surface we get a black boarder.