Most motherboards don't have onboard video... some server boards still commonly come with a basic graphics chip.
Intel CPUs usually have Intel HD graphics, which is suitable for multimedia playback and very light gaming. No where near as fast as an R9-270X. (There is no Z370 motherboard with onboard graphics suitable for serious gaming)
AMD APUs have onboard graphics comparable to low end AMD graphics cards. Still not really up to par with an R9-270X.