If you think about it, the electric field has to be moving close to the speed of light (strangely but not the electrons, but that is another story). So work out how much lag that cable would have at the speed of light. Almost none.
A slight delay for each component that forwards the HDMI might be reasonable but you can check this by trying a direct connection versus the routing through the AVR. Then you can subjectively determine the difference in lag. But don't assume any of that is the cable.
Any speed greater than 10.4 mbps is well outside any current HDMI chipset capability. So any cable that provides the excess capability is just wasted money and is a marketing ploy.