Question about ASUS H170-Pro

This mainboard is designed for Skylake processors with the LGA 1151 socket. However, the 4790K comes from the Haswell Refresh series with the LGA 1150 socket, so this mainboard is not compatible with the 4790K. For overclocking, I would advise a Z chipset.

Haswell Refresh: Z97 (LGA 1150) + 4790K

or

Skylake: Z170 (LGA 1151) + 6700K