A:Answer In regards to Hz, HDMI cables will do whatever your TV is capable of. Hz is a measure that, in layman's terms, is the refresh rate, i.e. how many times does the screen refresh in a second to produce the best possible picture. The higher the refresh rate (Hz), the less motion blur you see. Today's LED TVs have a standard refresh rate of 120-240 Hz (can go up a little more technically, but nobody is manufacturing the TVs to do so); older LCDs pretty much max out at 120 Hz; and older plasma televisions maxed out at 600 Hz, which is why you will hear a lot of people tell you that plasma televisions will still outperform most newer LED and 4K televisions (I tend to agree here having currently own a 4K and plasma). Even the earliest adaptations of the HDMI cable, pre-4K could handle the load of the 600 Hz plasma refresh rates with ease, the difference in those cables vs. the newer 4K HDMI cables is data speed. 4K needs 15 Mbps to produce the necessary 4K picture, and these cables can handle up to 18 Mbps.
Sorry for the long, drawn-out answer, but I hope this helps.