What are the best HDMI 2.1 settings for a 4K TV to get the highest quality picture and AI upscaling performance?

The Short Answer: Enable Enhanced Format and Match Source Resolution

For most 4K TVs, the single most important HDMI 2.1 setting is switching the port from "Standard" to "Enhanced" (or "Enhanced Format," "HDMI Ultra HD Deep Color," or "Full Bandwidth") in the TV's external input or general settings menu. This unlocks the full 48 Gbps bandwidth of HDMI 2.1, allowing 4K at 120 Hz, 10-bit or 12-bit color depth, and full-bandwidth HDR metadata. Without this change, your TV treats the port as HDMI 2.0, capping at 18 Gbps, which limits you to 4K at 60 Hz with 4:2:0 chroma subsampling. This setting is often buried in the TV's menu and is not enabled by default on many models from LG, Samsung, Sony, and TCL. If you are using a streaming device like an Apple TV 4K (second generation or later) or an Nvidia Shield TV, you also need to ensure the device's output is set to 4K SDR or HDR with the correct chroma sampling, and that the TV's input is set to "PC" or "Game" mode to reduce input lag and enable full chroma. For AI upscaling, the setting matters because the TV's internal upscaler (or an external device like the Nvidia Shield's AI-enhanced upscaling) works best when it receives a clean, uncompressed signal. If the HDMI port is locked to a lower bandwidth, the TV may receive a 1080p signal that it then upscales, but the upscaling quality is degraded by chroma subsampling and reduced color depth. The correct settings ensure that the source device sends the native resolution (e.g., 1080p or 1440p) and the TV's upscaler does the rest, or that the source device sends 4K and the TV applies only minor scaling. This article explains exactly which settings to change, why they matter, and how they interact with AI upscaling, based on the latest 2026 TV models and firmware updates.

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Understanding HDMI 2.1 Bandwidth and Why It Matters for 4K

HDMI 2.1 is the first major HDMI revision to support 48 Gbps bandwidth, which is more than double the 18 Gbps of HDMI 2.0. This bandwidth is necessary for 4K at 120 Hz with 10-bit color and full 4:4:4 chroma subsampling, which is the ideal signal for text and graphics. However, most 4K TVs are not configured to use this full bandwidth out of the box. Instead, they default to "Standard" mode, which limits the port to HDMI 2.0 speeds. This is a deliberate choice by manufacturers to avoid compatibility issues with older devices, but it means that unless you manually change the setting, you are not getting the full potential of your TV. For example, a 2025 LG C4 OLED TV has four HDMI 2.1 ports, but only one or two are enabled for full bandwidth by default; the others require you to go into the menu and select "Enhanced" for each port. The same applies to Samsung's Neo QLED models, where the setting is called "Input Signal Plus." On Sony Bravia TVs, it is "Enhanced Format" under the HDMI signal format menu. This setting is not just for gaming; it also affects streaming devices and Blu-ray players. If you have an Apple TV 4K (second generation, which supports HDMI 2.1), it can output 4K at 60 Hz with HDR and 4:4:4 chroma, but only if the TV's port is set to Enhanced. Otherwise, the Apple TV will fall back to 4:2:0, which reduces color detail, especially in red and blue gradients. For AI upscaling, the bandwidth matters because the upscaler in your TV or external device needs to receive the full-resolution signal without compression. If the port is limited to 18 Gbps, the source device may be forced to output 4K at 60 Hz with 4:2:0, which is fine for video but not for text or fine details. The upscaler then has to work with a signal that has already lost color information, resulting in softer edges and less accurate color reproduction. By enabling Enhanced Format, you ensure that the signal path is clean, and the upscaler can produce the best possible 4K image from lower-resolution sources.

Step-by-Step: How to Change HDMI 2.1 Settings on Popular TV Brands

The exact steps vary by brand, but the principle is the same: find the HDMI port you are using and switch it to the highest bandwidth mode. On LG TVs (2020 and later), go to Settings > All Settings > General > Devices > HDMI Settings. Here you will see a list of HDMI ports. Select the port that your device is connected to and choose "Enhanced" (or "Enhanced Format" on newer models). On some 2024 and 2025 LG models, there is also an option for "Enhanced VRR" or "Game Optimizer," but for general use, "Enhanced" is sufficient. On Samsung TVs, press the Home button, go to Settings > All Settings > Connection > External Device Manager > Input Signal Plus. Toggle this to On for the specific HDMI port. Note that Samsung's default is Off for all ports, so you must enable it for each port you use. On Sony Bravia TVs (2021 and later), go to Settings > Channels & Inputs > External Inputs > HDMI Signal Format. Select the port and choose "Enhanced Format" (which supports 4K at 120 Hz and VRR) or "Enhanced Format (Dolby Vision)" if you have a Dolby Vision-capable device. On TCL and Hisense TVs, the setting is often called "HDMI Mode" or "HDMI 2.1 Mode." For example, on TCL's 2025 QM8 series, go to Settings > Inputs > HDMI Mode and select "HDMI 2.1." On Hisense, it is under Settings > General > HDMI and CEC > HDMI Mode. After changing the setting, the TV may restart or the input may go blank for a few seconds. This is normal. Once enabled, you should verify that your source device is outputting the correct signal. For a streaming device like the Apple TV 4K, go to Settings > Video and Audio > Format and select "4K HDR" or "4K SDR" with the highest chroma option available (usually 4:4:4). For a gaming console like the PS5 or Xbox Series X, go to the console's display settings and confirm that it reports "4K at 120 Hz" and "10-bit" or "12-bit" color. If the TV's port is not set to Enhanced, the console will report a lower capability, such as 4K at 60 Hz with 4:2:2. This is the most common reason why people think their TV is not capable of 120 Hz, when in fact it is just a setting.

The Role of AI Upscaling and How HDMI Settings Affect It

AI upscaling is a feature found in many modern 4K TVs and external devices like the Nvidia Shield TV (which has a dedicated AI-enhanced upscaling mode). The purpose of AI upscaling is to take lower-resolution content, such as 1080p or 720p, and use machine learning algorithms to fill in missing detail and produce a 4K image. The quality of this upscaling depends on the quality of the input signal. If the input signal is compressed or has reduced chroma subsampling, the AI upscaler has less information to work with, and the output will be softer and less accurate. This is where HDMI 2.1 settings come into play. When you connect a device like the Nvidia Shield TV to a 4K TV, the Shield can output 4K natively, but if you are watching 1080p content, it will upscale it to 4K before sending it to the TV. The Shield's AI upscaling is generally considered superior to most TV's internal upscalers, but it requires a full-bandwidth HDMI connection to send the upscaled 4K signal without loss. If the TV's HDMI port is set to Standard, the Shield will still send 4K, but it may be forced to use 4:2:0 chroma subsampling, which reduces color detail. This is especially noticeable with text and fine patterns, where 4:2:0 can cause color fringing. By enabling Enhanced Format on the TV, you allow the Shield to send 4K with 4:4:4 chroma, which preserves all color information. Similarly, if you are using a TV's internal AI upscaler, the TV receives a 1080p signal from a cable box or streaming stick. The TV's upscaler then processes that signal. If the HDMI port is set to Standard, the TV may still receive 1080p, but the signal path is limited to 18 Gbps, which is fine for 1080p. However, if you have a 4K source that is being downscaled to 1080p by the source device (which some streaming apps do), the TV's upscaler will have to upscale it back to 4K, and the double conversion can degrade quality. The best practice is to set the source device to output its native resolution (e.g., 1080p for a cable box) and let the TV's upscaler handle the rest, or set the source to 4K if it has a good upscaler. In either case, having the HDMI port set to Enhanced ensures that the signal is not unnecessarily compressed.

Comparison: HDMI 2.1 Settings for Different Use Cases (Gaming, Streaming, PC)

The optimal HDMI 2.1 settings vary depending on what you are connecting. For gaming consoles like the PS5 or Xbox Series X, you want to enable Enhanced Format and also turn on VRR (Variable Refresh Rate) and ALLM (Auto Low Latency Mode) if available. These features reduce screen tearing and input lag, but they require the full bandwidth of HDMI 2.1. On LG TVs, you may need to enable "VRR" in the HDMI settings, and on Samsung, it is called "FreeSync Premium Pro." For PC users, the ideal setting is to set the input to "PC" mode (on LG and Samsung) or "Graphics" mode (on Sony), which disables some video processing and enables full 4:4:4 chroma. This is essential for reading text on a 4K desktop. For streaming devices like the Apple TV 4K or Nvidia Shield, the main consideration is whether you want the device to do the upscaling or the TV. The Nvidia Shield's AI upscaling is excellent, but it only works with certain apps and content. If you prefer the TV's upscaler, you should set the Shield to output 4K and let the TV handle the scaling. However, if you want the Shield to do the upscaling, you need to set the Shield to output 1080p and enable AI upscaling in the Shield's settings. In both cases, the HDMI port must be set to Enhanced to avoid chroma subsampling. The table below summarizes the recommended settings for each use case.

One of the most common mistakes is assuming that all HDMI ports on a TV are the same. Many TVs have only one or two HDMI 2.1 ports, and the rest are HDMI 2.0. For example, the Sony Bravia XR series has two HDMI 2.1 ports, but they are often labeled "HDMI 3" and "HDMI 4." If you plug your device into HDMI 1, you will not get 4K at 120 Hz, even if you enable Enhanced Format. Always check the TV's manual or the port labels on the back of the TV to identify which ports support HDMI 2.1. Another mistake is forgetting to change the setting on the source device as well. Even if the TV's port is set to Enhanced, the source device may be outputting a lower resolution or using 4:2:0 chroma. For example, the Apple TV 4K has a setting called "HDMI Output" that can be set to "YCbCr" or "RGB." For best quality, you should set it to "RGB High" if your TV supports it, but this requires the TV's port to be set to Enhanced. If you see a blank screen or flickering after changing settings, it is usually because the source device is not compatible with the higher bandwidth. In that case, you may need to use a different HDMI cable. Not all HDMI cables are certified for 48 Gbps. Look for cables that are labeled "Ultra High Speed" or "HDMI 2.1" and have the official certification logo. A cheap cable can cause intermittent signal loss or reduced bandwidth. Finally, many people forget to update their TV's firmware. Manufacturers often release updates that improve HDMI 2.1 compatibility and add new features. For example, LG released a firmware update in 2025 that fixed a bug where VRR was not working on certain ports. Always check for updates in the TV's settings menu.

When to Act: Should You Change These Settings Now?

If you have a 4K TV and any device that supports HDMI 2.1, you should change the HDMI port setting to Enhanced immediately. This includes not only gaming consoles and streaming devices but also newer Blu-ray players and soundbars. The setting is free, takes less than two minutes to change, and has no downside for most users. The only exception is if you have an older device that does not support HDMI 2.1 and causes compatibility issues when the port is set to Enhanced. In that case, you can leave the port on Standard for that device, but you should use a different port for your modern devices. For AI upscaling, the timing is also important. If you are using a TV with AI upscaling, you want to ensure that the signal path is clean, so enabling Enhanced Format is a prerequisite. If you are using an external upscaler like the Nvidia Shield, you should also check that the Shield's firmware is up to date, as the AI upscaling algorithm has been improved over time. As of August 2026, the latest Nvidia Shield TV (2019 model) still receives updates, and the AI upscaling is considered one of the best in the market. If you are planning to buy a new TV, look for models that have all HDMI ports supporting HDMI 2.1, such as the LG C4 or Samsung QN80F. Some budget TVs, like the TCL Q6, have only one HDMI 2.1 port, which may be a limitation if you have multiple devices. In that case, you may need to use an HDMI 2.1 switch, but be aware that not all switches support full 48 Gbps bandwidth. The best time to change the settings is when you first set up the TV, but if you have not done it yet, do it now. The improvement in picture quality, especially for 4K HDR content and AI upscaling, is noticeable, and you are essentially leaving performance on the table if you do not.

The Cost of Getting It Wrong: What You Are Missing

The cost of not changing your HDMI 2.1 settings is not monetary, but it is a significant loss in picture quality and performance. For example, if you have a 4K TV with a 120 Hz panel, but you leave the HDMI port on Standard, you will only get 60 Hz. This is particularly noticeable in sports and fast-action scenes, where motion will be less smooth. For gaming, the difference between 60 Hz and 120 Hz is night and day, with lower input lag and smoother motion. According to a 2026 test by tech-insider.org, the input lag on a 4K TV at 120 Hz is around 5.5 ms, compared to 6.8 ms at 60 Hz, which is a 20% improvement. For AI upscaling, the difference is more subtle but still important. A 1080p signal upscaled to 4K with full chroma will have sharper edges and more accurate colors than one with 4:2:0 subsampling. In a side-by-side comparison, the difference is most visible on text and fine patterns, such as the texture of fabric or grass. If you are watching a lot of older content, like DVDs or 720p streams, the AI upscaler has to work harder, and the quality of the input signal matters even more. By not enabling Enhanced Format, you are essentially degrading the signal before the upscaler even sees it. This is why the setting is often described as "unlocking" your TV's full potential. It is not a marketing gimmick; it is a technical necessity. The good news is that the fix is simple and free. The only cost is the time it takes to navigate the TV's menu. If you are not sure whether you have changed the setting, you can check by looking at the TV's display information. On most TVs, you can press the Info button on the remote to see the current resolution and frame rate. If it shows 4K at 60 Hz, you are likely on Standard. If it shows 4K at 120 Hz, you are on Enhanced. For a more accurate check, you can use a test pattern from a device like the Spears & Munsil UHD HDR Benchmark, which can display the chroma subsampling and color depth. This is a useful tool for calibrating your TV and ensuring that you are getting the best possible signal.

Future-Proofing: HDMI 2.1 and Beyond in 2026

As of August 2026, HDMI 2.1 is the standard for 4K TVs, but the technology is evolving. The HDMI Forum has announced HDMI 2.2, which will support even higher bandwidth (up to 96 Gbps) and is expected to be available in 2027. However, for now, HDMI 2.1 is sufficient for 4K at 120 Hz and even 8K at 60 Hz. The key is to ensure that your TV's HDMI ports are configured to use the full bandwidth. Many 2026 TV models, such as the LG G5 and Samsung QN90F, come with all ports supporting HDMI 2.1, but they still default to Standard mode. This is a common complaint among users, and some manufacturers have started to change the default to Enhanced. For example, the 2026 Sony Bravia 9 series has a setting called "Auto Enhanced" that automatically switches to Enhanced when it detects an HDMI 2.1 device. However, this is not foolproof, and it is still recommended to manually check the setting. For AI upscaling, the future is even more promising. LG has introduced a 5K AI upscaling technology in its 39GX950B monitor, which uses a dedicated AI processor to upscale 4K content to 5K without a GPU. This technology is expected to trickle down to TVs in the coming years. The Nvidia Shield TV's AI upscaling is also being improved, and there are rumors of a new Shield model with even better upscaling. In the meantime, the best way to future-proof your setup is to use high-quality HDMI 2.1 cables and to keep your TV's firmware updated. The HDMI 2.1 setting is not a one-time thing; you may need to re-enable it after a firmware update or if you change devices. It is also a good idea to label your HDMI cables and ports so that you know which ones are set to Enhanced. This will save you time in the future when you add new devices.

Conclusion: The One Setting That Changes Everything

In summary, the HDMI 2.1 setting on your 4K TV is the single most impactful change you can make to improve picture quality and AI upscaling performance. It is a simple menu option that is often overlooked, but it unlocks the full bandwidth of the HDMI connection, allowing for higher resolutions, frame rates, and color depth. Without it, you are not getting the full potential of your TV, and AI upscaling will produce softer, less accurate images. The setting is available on all major TV brands, and the process takes less than two minutes. Whether you are a gamer, a movie enthusiast, or a PC user, you should enable Enhanced Format on every HDMI port that you use with a modern device. The only exception is if you have an older device that causes compatibility issues, but even then, you can use a different port. As of 2026, there is no reason not to change this setting. It is free, safe, and has no downsides for the vast majority of users. So, go to your TV's settings right now and make the change. Your eyes will thank you.