HDMI 2.0 vs. HDMI 2.1: What's the difference?

There's a new HDMI cable in town—but do you need it?

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I managed to get my wires crossed in a recently published TV review.

While describing the TV's hardware, I accidentally referred to its HDMI ports as being of the "HDMI 2.0" variety. In reality, however, this TV features HDMI 2.1 ports. It's what we in the publishing biz call "a real oopsie-daisy."

After (rightfully) getting dragged in the comments for this error, I promptly corrected it. The entire mix-up, though, got me thinking about HDMI 2.1 and its advantages over HDMI 2.0—it might not seem like the most thrilling topic in the world, but if our readers' comments are any indication, it's an important one.

So, what's the difference between HDMI 2.0 and 2.1, and most importantly, do you need to buy HDMI cables all over again? Let's get into it.

What is HDMI 2.1?

HDMI 2.1 is the newest version of the HDMI interface, concerning both HDMI ports and the cables themselves. At the time this article is being written in mid-2019, HDMI 2.1 is in the nascent stage of its lifecycle—we're just now beginning to see AV companies addressing HDMI 2.1 in their current- and next-gen products.

Some high-end TVs, for instance, are starting to come with HDMI 2.1-compliant ports, and ultra-high speed, HDMI 2.1-compliant cables are right around the corner. The next generation of video game consoles from Sony and Microsoft will support HDMI 2.1, too.

The new HDMI interface will support higher performance standards than the current interface, HDMI 2.0 (or 2.0b, to be more specific). In other words, the exciting TV features of tomorrow—8K resolution, for example—will rely on HDMI 2.1.

What's the difference between HDMI 2.0 and HDMI 2.1?

Most contemporary mid-range and high-end TVs offer at least one HDMI 2.0 port, and if you've bought a TV in the last couple of years, there's a good chance that all of your TV's HDMI ports are either of the 2.0a or 2.0b variety. The difference between 2.0a and 2.0b is relatively minor, so let's focus on 2.0 versus 2.1.

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Essentially, it all comes down to bandwidth: The current bandwidth capacity for HDMI 2.0 is 18 Gbps, but HDMI 2.1 clocks in at a robust 48 Gbps. This increase in bandwidth allows HDMI 2.1 to transfer way more information; in a nutshell, this means higher-resolution video and higher frame rates.

Currently, HDMI 2.0 cables are needed to achieve a 4K picture at 60 FPS or an 8K picture at 30 FPS. HDMI 2.1, on the other hand, promises 4K resolution at 120 FPS, 8K resolution at 60 FPS, and a ceiling that will ultimately support 10K resolution—whenever the industry happens to reach that point.

Gaming Input Lag
Credit: Reviewed

Gamers will likely be the first to feel the advantages of HDMI 2.1, since video game developers are already promoting 4K games that run at 120FPS.

There's also a host of other benefits to HDMI 2.1 that are a little more in the weeds but nevertheless exciting. For example, HDMI 2.1 supports something called "Dynamic HDR," which allows HDR metadata content to be adjusted on a frame-by-frame basis. HDMI 2.1 also features eARC, a more robust version of Audio Return Channel, which allows high-quality, uncompressed audio signals to be transferred via HDMI cable.

With consumer-facing 8K content still a long way from primetime, gamers will likely be the first group of people to feel the advantages of HDMI 2.1, since 4K games will be able to run at 120 FPS with the proper hardware. In addition, HDMI 2.1 features Variable Refresh Rate (VRR) and Quick Frame Transport (QFT)—two features that will reduce latency and possibly eliminate input lag altogether.

Do I need new cables for HDMI 2.1?

You'll eventually need new HDMI cables to enjoy all that HDMI 2.1 has to offer—but you're probably fine for now.

Ultra-high speed HDMI 2.1-compliant cables are still relatively hard to come by, and in fact, official compliance test specifications are still in the process of being ironed out. Simply put, consumers don't yet have a reliable way to buy HDMI 2.1 cables—the ones that are available probably haven't been tested and certified by HDMI Licensing Administrator, Inc.. They might claim to meet all of the required 2.1 benchmarks, but without an official certification, your mileage may vary.

Eventually, you'll need HDMI 2.1 cables to take advantage of what the new interface has to offer, but don't worry about buying them just yet.

Additionally, unless you own one of the very few TVs with HDMI 2.1-compliant ports, you probably won't have to worry about buying new cables, since your TV lacks the inputs required to take advantage of those cables in the first place.

Don't worry: HDMI 2.1 is backwards compatible, so all of your current HDMI cables will still work in the future with HDMI 2.1-supported devices

Here's the bottom line:

HDMI 2.1 will transform how we watch and enjoy content—be it film, games, or streaming TV shows. For the time being, however, most consumers needn't worry about HDMI 2.1 since there isn't much content available yet that really takes advantage of its capabilities. Plus, HDMI 2.1 inputs are just now making their way into the TV market, and the testing procedures to certify the cables themselves haven't even been finalized yet.

In 2020, however, things will begin to shift: The next generation of gaming consoles will begin to take advantage of what HDMI 2.1 has to offer, and both TV manufacturers and content creators will begin to focus on 8K resolution.

Until then, hang on to your HDMI 2.0 cables—they're still worth saving.

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