When it comes down to 4K TV, you do not need to pick up special HDMI cables. The HDMI cable standard can impact color and resolution, but newer versions are not required for 4K TV.
Any HDMI cable labeled high-speed (18 Gbps) transfer speed is 4K compatible. Check the cable itself. Look for printing on the cable itself, which should say “high speed with ethernet" or something similar. The better cables print the specs on the cable part.
HDMI 2.1 is only needed if you want to use HDMI with 4K over 60Hz. This applies to consoles, as on PC you can get the same performance with DisplayPort 1.4, which is readily available. So, it's likely adding HDMI 2.1 cables and expense to your setup is not something you need to worry about now.
4K HDMI 2.0 cables deliver 4K at 60 frames per second (fps), while 8K HDMI 2.1 cables deliver 8K content at 60fps or 4K content at 120fps, since less data is required to transmit 4K content. The bottom line is that if you have 4K content, you'll get twice the frames per second using an 8K cable.
As long as you have at least HDMI 1.4, 120Hz is doable on your compatible TV or monitor. You can even do up to 144Hz if your display supports it.
120Hz Displays Don't Need “120Hz” HDMI Cables
What's important to understand is the simple fact that these new 120Hz displays don't need special cables. The refresh rate happens AT THE DISPLAY not at the source. That means that the 120Hz or 240Hz signal never actually travels along the cable.
For resolutions near 4K, it's recommended to use an HDMI cable that is no longer than 3 meters (10 feet). After that distance, the signal can start to degrade. For lower resolutions, the reliable distance is much longer, with the most common being 15 meters (50 feet).
Gold-plated cables provide the same image quality as the source – high quality. Also, there is a theoretical improvement in clarity of the signals being transmitted as gold-plated cables are better conductors of electricity compared to regular HDMI cables.
The majority of HDMI connectors in use today are the Type A (Standard), Type C (Mini) and Type D (Micro) shown below. HDMI Type B (Dual Link) was developed for very high-resolution displays but was never used.
A 2.1 HDMI cable can be as long as 50 feet or over. As a cable with a higher frame rate, the greater the distance the signal has to travel, the more quality loss there will be. For the best length and definition balance, we wouldn't recommend going over 20 feet.
You don't absolutely need HDMI 2.1 to reach 120Hz or even 144Hz refresh rates, but it is important for supporting both high refresh rates and high resolution at the same time.
HDMI 2.1 allows for higher resolutions like 8K and higher frame rates of up to 120 frames per second (fps). Resolution improves the clarity and sharpness of the picture, which means you can simply see more details, and have less distance to the screen or a bigger screen without noticing any pixels.
The “4k HDMI” label is mostly marketing, so it doesn't mean a specific feature that will improve image quality. But if you have any cables past the HDMI 1.4 version, then they will be moving the same 4k image across the cable regardless of any marketing.
An expensive HDMI doesn't produce richer colors or crisper sound than cheaper versions. However, an HDMI cable made with better materials can be more durable, and support higher bandwidth at longer distances, but it won't offer any difference with the picture quality.
With any resolution, keep in mind that if you're getting a 4K signal, it's not possible for a different cable to make that 4K look better. The only differences in cables is one will allow you to get a stable, 4K image, and another one won't.
The length of an HDMI cable does have a negative effect on signal quality, with manufacturers generally not recommending cables over 20 feet.
A high quality HDMI cable does not necessarily mean purchasing an extremely expensive cable, it just means buying a well-made High Speed HDMI cable that is compact, durable, and from a reputable company. If it looks flimsy and cheap, it probably is and it may not last very long or provide the quality that you want.
As such, if you live in an area where metal corrosion is a problem, a gold HDMI cable will help it last longer. Corrosion occurs due to high humidity and affects people who live by the sea, a river, or on a boat.
HDMI cables are interactive, so you can use an HDMI cable that supports 4K on your 1080p TV. For this same reason, you can use a high-speed HDMI cable on any digital TV, even a non-Smart TV or non-HD TV.
Like many audio, video, and data cables, HDMI cords can suffer from signal degradation at longer lengths—50 feet is generally considered the maximum reliable length. And it's rare to see an HDMI cable longer than 25 feet in a store.
All in all, if you have or plan on getting a gaming PC or a console that supports 120Hz, you should definitely get a 120Hz TV as it makes for a more responsive and immersive gaming experience. Keep in mind that to get the most out of 120Hz, you should also be able to maintain around 120FPS (Frames Per Second).
Do you need a 90Hz or 120Hz refresh rate? Absolutely not — much in the same way you don't “need” a camera, flashlight, or pinball game on your smartphone. But anyone who has used a device with a 90Hz or 120Hz refresh rate will tell you the massive difference it makes to the way your device feels.
HDMI Specification HDMI 2.1a feature highlights include: Higher video resolutions support a range of high resolutions and faster refresh rates including 8K60Hz and 4K120Hz for immersive viewing and smooth fast-action detail.