2400mhz or 2666mhz ddr4

Solution
Until the upgrade is in place will prob be limited to running at 2133, if keeping the same CPU with the mobo upgrade 2666 might be pushing the CPU's MC to it's upper ends. If price the same go the 2666


my cpu is i3 6100
mobo: asus h110m D

what is better ddr4 ram mhz?
i upgrade my mobo @z170 soon