How to Enable 4K HDR and 120Hz Over HDMI

This guide walks you through getting your TV or monitor to display 4K resolution, HDR (High Dynamic Range), and a 120Hz refresh rate over a single HDMI connection. You’ll learn what hardware and settings are required, how to configure your devices step by step, and how to fix common issues when things don’t work as expected.

What You’ll Need

A 4K display that supports 120Hz and HDR (check the specs or manual).
A source device (PC, game console, streaming box) with an HDMI 2.1 output.
An Ultra High Speed HDMI cable (certified for 48Gbps).
For PC: a graphics card with HDMI 2.1 (NVIDIA RTX 30/40 series, AMD RX 6000/7000 series) and a recent operating system (Windows 10/11).
For consoles: Xbox Series X/S or PlayStation 5 (both have HDMI 2.1).

Step-by-Step

Check your display’s HDMI port version. Look in the manual or on the port itself. For 4K 120Hz, you need HDMI 2.1 (or DisplayPort 1.4 with DSC if using a monitor). Some TVs label ports as “HDMI 2.1” or “8K” – use that one.
Connect with a certified Ultra High Speed HDMI cable. Plug it firmly into both devices. Avoid using long cables (over 3 meters) unless they are active optical cables.
Power on your display and source device. Make sure both are fully booted before changing settings.
On your TV/monitor, enable the enhanced HDMI mode. This is often called “HDMI UHD Color,” “Enhanced Format,” “HDMI 2.1 Mode,” or “Input Signal Plus.” Go to the display’s settings menu, find the HDMI input you’re using, and turn on the enhanced mode. Without this, the display may only accept up to 4K 60Hz or 1080p 120Hz.
On Windows 10/11: Right-click the desktop and select Display settings. Scroll down to Advanced display settings. Under “Choose a display,” select the TV/monitor. Check that the refresh rate shows 120Hz. If not, click Display adapter properties, go to the Monitor tab, and set the screen refresh rate to 120Hz. Also, under Display settings, ensure the resolution is set to 3840 x 2160.
On Xbox: Go to Settings > General > TV & display options. Under Resolution, select 4K UHD. Under Refresh rate, choose 120Hz. Make sure “Allow 4K” and “Allow HDR” are checked under Video modes.
On PlayStation 5: Go to Settings > Screen and Video > Video Output. Set Resolution to 2160p (4K). Set VRR (if your TV supports it) to Automatic. Under “120Hz Output,” select Automatic. Also enable HDR under “HDR” set to On When Supported.
Enable HDR on the source. On Windows, open Settings > System > Display, and toggle on “Play HDR games and apps” (or use the Win+Alt+B shortcut). On consoles, HDR is usually automatic when the content supports it and the TV is set to enhanced mode.
Test the result. Play a game or video that supports 4K HDR and 120Hz (e.g., a compatible console game or a 4K 120fps YouTube video). Check the display’s info overlay (often accessible via an info button on the remote) to confirm the resolution, HDR, and refresh rate.

Common Mistakes

Using an old HDMI cable. Standard or High Speed cables (18Gbps) cannot carry 4K 120Hz HDR. You need Ultra High Speed (48Gbps).
Plugging into the wrong HDMI port. Many TVs have only one or two HDMI 2.1 ports. Check the labels.
Not enabling enhanced HDMI mode. Even with a good cable, the TV will default to lower bandwidth unless you turn on the enhanced setting.
Assuming all 4K 120Hz displays support HDR. Some monitors do 4K 120Hz but lack HDR, or HDR is poor. Check the specs.
Forgetting to update GPU drivers. Outdated graphics drivers can limit refresh rate options.

Tips

Use a cable that is certified by HDMI Licensing Administrator – look for the “Ultra High Speed” label with a QR code.
Keep cable runs short. If you need a long cable, choose an active optical HDMI 2.1 cable.
On PC, if 120Hz doesn’t appear, try setting the resolution to 4K and then changing the refresh rate in the NVIDIA Control Panel or AMD Radeon Software.
Enable Game Mode on your TV to reduce input lag – this is separate from VRR.
If your TV supports VRR (Variable Refresh Rate), enable it on both the TV and the source for smoother gameplay.

Troubleshooting

No 120Hz option: Check that the display’s HDMI port is 2.1 and enhanced mode is on. Try a different HDMI port. On PC, make sure the GPU is using the HDMI 2.1 port (not a DisplayPort to HDMI adapter).
HDR is grayed out: Ensure the display’s HDR mode is enabled (often in the same enhanced settings). Also, the source must be set to HDR output. On Windows, HDR may require the display to be set to 4K resolution first.
Screen flickers or goes black: This often happens when the cable is insufficient. Replace with a certified Ultra High Speed cable. Also, try lowering the refresh rate to 120Hz (not 144Hz) if your display supports it.
Picture is washed out with HDR on: Check your display’s HDR tone mapping settings. On Windows, use the HDR calibration tool (Windows 11) or adjust the SDR/HDR brightness slider.
Console says 120Hz not supported: Make sure the TV is set to the correct input and that the enhanced mode is on. Also, some TVs require the input to be named “PC” or “Game” to unlock 4K 120Hz.

Frequently Asked Questions

Q: Do I need an HDMI 2.1 cable for 4K 120Hz?
A: Yes, 4K 120Hz with HDR requires about 40Gbps of bandwidth, which only Ultra High Speed HDMI 2.1 cables support. Older cables will not work.

Q: Can I get 4K 120Hz with HDMI 2.0?
A: No. HDMI 2.0 supports up to 4K 60Hz (or 4K 120Hz only with chroma subsampling and no HDR, which is not practical). You need HDMI 2.1.

Q: Why does my PC show 120Hz but not HDR?
A: HDR may be disabled on the display or the source. Check Windows HDR settings and the TV’s enhanced mode. Also, some displays only support HDR at certain refresh rates – try 120Hz instead of 144Hz.

Q: Is 4K 120Hz worth it?
A: If you play fast-paced games or watch sports, yes – the higher refresh rate makes motion smoother. For movies, 24fps content is unaffected, but HDR is still beneficial.

Q: Does VRR (Variable Refresh Rate) require HDMI 2.1?
A: For 4K VRR, yes. HDMI 2.1 includes VRR support. Some displays support VRR over HDMI 2.0, but it’s rare and limited.

Q: What if my TV only has one HDMI 2.1 port?
A: Use that port for your 4K 120Hz device. If you have multiple, you may need an HDMI 2.1 switch (but they are expensive and can cause issues).

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

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