HDMI 2.1

HDMI 2.1 is the version of the HDMI standard that carries enough bandwidth for modern console gaming. The older HDMI 2.0 tops out at 4K 60Hz. HDMI 2.1 raises that ceiling substantially, and with it comes the set of features current consoles depend on.

What it enables

• 4K at 120Hz — impossible over HDMI 2.0 at full quality.
• VRR — variable refresh rate, which removes tearing and stutter.
• ALLM — the TV switches to game mode automatically.
• eARC — higher-quality audio passed to a soundbar or receiver, including formats like Dolby Atmos.

Without HDMI 2.1, a PS5 or Xbox Series X is limited to 4K 60Hz and loses VRR. The console still works perfectly well — you simply cannot reach the higher modes.

The trap worth knowing

Many televisions advertise HDMI 2.1 but implement it on only one or two ports out of four. If you are connecting a console and a soundbar, check which specific ports support it, not just that the set lists the feature.

There is a second trap on the TV side: full bandwidth is often disabled by default. Depending on the brand it is called HDMI Deep Color, HDMI UHD Color, Input Signal Plus or Enhanced Format, and until you switch it on for that port you will not get 4K 120Hz or VRR no matter what the console reports.

Do I need a special HDMI cable for 4K 120Hz?

Yes. You need an Ultra High Speed HDMI cable, rated for 48Gbps. An older "High Speed" cable will often work at 4K 60Hz and then fail at 120Hz, sometimes with a flickering or blank screen rather than an obvious error.

The good news is that the cable supplied with a PS5 or Xbox Series X is already the correct type. Use it. If you need a longer one, look specifically for the Ultra High Speed label rather than assuming price indicates quality — an expensive cable that is not rated for 48Gbps is no better than a cheap one that is.