HDMI 2.1 "Ultra High Speed HDMI Cable" is the official name for 8K HDMI cables.

Even though these 48Gbps cables are designed to support future technologies, 8K HDMI cables already have practical uses. Here are reasons to consider buying an HDMI 2.1 cable:

If your Apple TV 4K flickers or flashes - Several Apple TV 4K users complain of intermittent screen flickering or a flashing white light, especially while using Dolby Vision or other HDR10 formats. Apple recommends using an 8K HDMI cable for Apple TV 4K.

If you play video games in 4K - Next-gen consoles like the PlayStation 5 (PS5) and Xbox Series X use the HDMI 2.1 Specification and so do ultra-high end graphics cards like Nvidia’s RTX 3080 and RTX 3090. HDMI 2.1 cables support 4K refresh rates of up to 120Hz, which is a standard that is now supported by high-end gaming monitors.

If you edit 8K video - Video-editing workstations that support 8K resolution require a DisplayPort 1.4 or HDMI 2.1 connection to display full resolution imagery on an 8K monitor.

If you listen to Dolby Atmos or DTS:X audio - The best surround sound formats (like DTS Master, DTS:X, Dolby TrueHD, and Dolby Atmos) use HDMI-eARC, a standard that is best supported by 48Gbps HDMI cables.

If you're semi-permanently wiring a home theater - Using a next-generation HDMI cable today can save some frustration tomorrow: Nobody wants to re-snake cables through a wall or ceiling.

If your Dolby Vision TV supports 4:4:4 chroma subsampling - A 4K 60Hz signal using uncompressed Dolby Vision HDR requires 24.06Gbps of bandwidth: That’s more than HDMI 1.4 or HDMI 2.0 can handle. HDMI 2.1 can also support 8K video at up to 60Hz, which some 8K TVs are capable of handling.

There Are No Certified HDMI 2.1 Cables (Yet)

A growing list of devices support the HDMI 2.1 specification, but as of now, there are no certified HDMI 2.1 cables. This is a frustrating state of affairs considering that the HDMI 2.1 specification was announced in early 2017 and the HDMI Forum has a mandatory certification program that still isn’t off the ground.

In the meantime, the HDMI 2.1 cables below are manufactured by companies that sell other certified-HDMI cables. That's no guarantee that these cables meet the full HDMI 2.1 specification, but it instills confidence.

Don’t Trust Any HDMI 2.1 Cable Longer Than 10 Feet

All passive HDMI cables (i.e. copper wire cables) lose signal strength and handshake capabilities over long runs; this problem only worsens with high resolution audio and video content. That’s why the HDMI Forum predicts that the maximum HDMI 2.1 passive cable length “will be approximately 2 to 3 meters.”

For longer cable runs, an optical HDMI is required. But, these speciality cables can cost hundreds of dollars, and considering that there are no certified HDMI 2.1 optical cables on the market, this is a risky proposition.