8K capable HDMI cables

8K presents another issue for the early adopter: the bandwidth required is going to be ridiculous. Most 4K content providers recommend you have an internet connection in the 20 Gbps range. 8K, even with everything else the same, has four times as many pixels. That doesn’t equate exactly to a 4x increase in data or bandwidth, but, and this is just a guess, a connection requirement in the 40 to 50 Gbps range wouldn’t be unexpected. The vast majority of people don’t have that kind of internet speed.

Interestingly, we’ve already got the physical connection thing sorted if any 8K media streamers hit the market. HDMI 2.1 is capable of 8K resolutions and more. But before you rush out and stock up on HDMI 2.1 cables, keep in mind there will almost certainly be a new standard between now and wide adoption of 8K. So those cables might be obsolete, despite their current forward-looking appearance.

All of the major 8K TV makers say that their sets have HDMI 2.1 inputs capable of handling the 48 Mbps bandwidth required for the highest resolution and frame-rate combinations (8K and 60 frames per second and 4K at 120 fps). We also got a look at some new, higher-bandwidth HDMI cables.

 

What is HDMI 2.1 anyway?

HDMI 2.1 expands on the current HDMI 2.0 connection standard, a collection of features and capabilities that allows source devices (game consoles, streamers, Blu-ray players, etc.) to send audio and video to TVs.

For most people with current and even near-future 4K TVs, HDMI 2.1 isn’t a big deal, and HDMI 2.0 is plenty. It will handle 4K resolution at up to 60 fps, and even some varieties of 8K (24 and 30 fps). It also doesn’t require a new HDMI 2.1 cables. But for the people who buy an 8K TV — the full version of HDMI 2.1 is worth considering. Here’s what it offers.

 

Not all HDMI 2.1 is Full HDMI 2.1

HDMI Licensing is allowing companies to claim HDMI 2.1 compliance even if the TV can’t do all of 2.1’s features. So, for instance, a company with a TV that can do eARC and VRR, but not the 48 Gbps required for 8K/60, could still say their TV is HDMI 2.1. They’re only allowed to do this if they also explain which specific features the TV supports.

There’s no reason you should be looking for Ultra-High-Speed HDMI cables right now. Once called “48G” and already incorrectly labeled as “HDMI 2.1” cables, they offer no benefit to your current 4K TV.

 

HDMI hardware limitations

HDMI cables are actually multiple smaller wires all bundled together with rubber. To keep the overall cable diameter small, so it’s bendable and not impossible to use in your house, each of the strands inside has to be kept as small as possible. Other parts, like shielding, can shrink too, but all only to an extent. The thinner these strands of copper are, the more signal gets lost over the length of the wire. Too thin, and you won’t get anything, or the cable won’t be able to transfer really high resolutions. Go the other way, and make all the parts thick, and it would be like trying to connect your TV and cable box with a garden hose, and not one of those fancy flexible ones either.

it won’t be practical to do 48 Gbps using traditional copper wires over longer lengths, even just a few meters. The longer ones are exceptionally thick. Fine for some situations, certainly, but if you’re trying to run it around corners or tight spaces, it’s going to be a hassle.

However, this potential limitation might not be an issue. The price of optical HDMI cables has dropped significantly in recent years. New chip design allows optical HDMI cables to be similar in price, and possibly cheaper than copper cables. They’ll also only be 3mm thick. Despite being optical, i.e. requiring a change from electrons to photons and back again, they likely wouldn’t need any external power. They’ll pull it from the HDMI connection itself.

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