My CSV-1477 can achieve the refresh rate of 30 Hz @ 3840×2160 (DELL UP2414q), but I cannot select the refresh rate of 60 Hz.
I found the above phenomenon in my notebook (on-board graphic), first, and also found in my desktop PC (MSI NVIDIA GeForce GTX1070 8GB).
Though my desktop PC usually works with two 4K monitors (dual UP2414q via DisplayPort cables) at 60 Hz with GeForce GTX 1070, it cannot do the same thing via CSV-1477.
(So I suppose that the cables and the monitors are ready for 4K60p.)
USB connection seems to be successfully established because the output signal itself is produced (at 30 Hz).
I suspect that the problem comes from the device failure.
If any one has a similar experience or knows the solution, please post some comments here.