Lenovo Legion Slim 7i Gen 8 Intel Core i7-13700H HDMI 2.1 4K 120Hz Not Working Fix

The Lenovo Legion Slim 7i Gen 8 is a thin gaming laptop featuring an HDMI 2.1 port capable of 4K at 120Hz output. When connecting to a 4K 120Hz TV or monitor, some users find the maximum resolution offered is only 4K at 60Hz, or the display is limited to 1080p at 120Hz, blocking the full HDMI 2.1 bandwidth that this port should deliver.

This guide walks through the most effective fixes for HDMI 2.1 not delivering 4K 120Hz on the Lenovo Legion Slim 7i Gen 8 with the Intel Core i7-13700H processor.

Why 4K 120Hz Is Not Available over HDMI

• HDMI cable does not support 48Gbps bandwidth (HDMI 2.0 cable used instead of 2.1)
• Monitor or TV HDMI port is HDMI 2.0, not 2.1
• NVIDIA driver not exposing the full 4K 120Hz mode
• TV HDMI Enhanced Format or 4K Signal setting not enabled
• HDMI 2.1 mode not selected on the monitor side

Step-by-Step Fixes

Fix 1: Use a Certified HDMI 2.1 Cable (48Gbps)

This is the single most common cause of missing 4K 120Hz modes. HDMI 2.0 cables physically cannot carry the 48Gbps bandwidth required for 4K 120Hz:

• Check the cable packaging or label for HDMI 2.1 or 48Gbps certification.
• Cables labelled only as HDMI 2.0 or High Speed HDMI are limited to 18Gbps — insufficient for 4K 120Hz.
• Replace with an Ultra High Speed HDMI cable (48Gbps certified) and test immediately.

Fix 2: Enable HDMI Enhanced Format on the TV or Monitor

Many 4K TVs disable HDMI 2.1 features by default and must be manually enabled:

1. On the TV, press the Home or Settings button.
2. Navigate to Picture > HDMI Signal Format (Sony), General > External Device Manager > HDMI UHD Color (Samsung), or the equivalent setting for your brand.
3. Set the HDMI input you are using to Enhanced Format or HDMI 2.1.
4. Return to the Windows display settings and check whether 4K 120Hz now appears.

Fix 3: Update the NVIDIA Driver

NVIDIA drivers sometimes require an update to expose the full HDMI 2.1 bandwidth mode:

1. Open GeForce Experience and install the latest Game Ready Driver with a clean install.
2. After restart, right-click the desktop and open NVIDIA Control Panel > Display > Change resolution.
3. Select the TV and check whether 4K at 120Hz now appears in the resolution list.

“The cable was the problem. My old HDMI cable from a previous monitor was HDMI 2.0. A new 48Gbps HDMI 2.1 cable made 4K 120Hz appear in Windows display settings immediately.”
— Amirul Hafeez, content creator

Fix 4: Set 4K 120Hz in NVIDIA Control Panel

After ensuring the cable and display support HDMI 2.1, set the resolution manually:

1. Open NVIDIA Control Panel > Display > Change resolution.
2. Select the connected TV or monitor.
3. Choose 3840 x 2160 resolution and set refresh rate to 120Hz.
4. Click Apply. If 120Hz is not in the dropdown, the cable or TV HDMI enhanced format setting needs attention first.

Fix 5: Verify the Laptop HDMI Port Is 2.1

Confirm the Legion Slim 7i Gen 8 HDMI port specification by checking the product specification sheet on the Lenovo website. The HDMI 2.1 port on this model is rated for 4K at 120Hz and 8K at 60Hz. If after all fixes the mode is still unavailable, run Dell Command Update (or Lenovo Vantage system update) and install any available BIOS updates that may address HDMI output mode reporting.

Frequently Asked Questions