A High Speed HDMI Cable is the best way to ensure that you have the ability to pass all the signals authorized in the latest HDMI feature specification. Ferrite Cores are small magnetic blocks wrapped around the end of a cable. They are used to suppress EMI/RFI electronic noise on the cable by absorbing the unwanted high frequencies and dissipating them as very low-level heat. This is the simplest and cheapest form of electronic noise reduction and is most effective on small gauge cabling, which is inherently more susceptible to electronic noise interference than thicker cables.