4K HDMI cables (are nonsense)

You do not need a new HDMI cable for Ultra HD 4K (probably).

4K HDMI cables
HDMI.org/Geoffrey Morrison

With the slow and inevitable transition to Ultra HD 4K happening whether it's necessary or not, it's not surprising that cable manufacturers are jumping at the chance to sell new and more expensive "4K" HDMI cables.

But guess what -- you don't need 4K HDMI cables, because your current HDMI ones can probably do 4K just fine. Seriously.

Here's why.

In case you missed the tetralogy on HDMI cables, check out Why all HDMI cables are the same, Why all HDMI cables are the same, Part 2, Still more reasons why all HDMI cables are the same, and the HDMI Cable Buying Guide.

You'd think I'd have said my piece by now, but apparently not. Here's the short version. There are only four kinds of HDMI cables:

High-speed with Ethernet
High-speed without Ethernet
Standard-speed with Ethernet
Standard-speed without Ethernet

There's no reason to get standard-speed cables anymore, as the price difference is negligible between those and the high-speed versions. As per the current HDMI 1.4 spec, in order for an HDMI cable to be considered high-speed, it must be able to pass 3,840x2,160 pixels at up to 30 frames per second (and 4,096x2,160 at 24 frames per second).

This means that even the cheapest high-speed HDMI cable can pass the maximum resolution possible with the current generation of Ultra HD 4K TVs.

And guess what -- this isn't just numbers on a page, or theoretical knowledge. I reviewed one of the first 4K TVs and plugged in a $2.50 HDMI cable between it and a 4K source. Guess what? It worked perfectly. So did the cheap HDMI cable Senior Editor David Katzmaier used in his review. I also used a 40-foot HDMI cable (with RedMere) that worked perfectly.

Since 3,840x2,160/30 is the maximum in the current HDMI spec, it doesn't matter if you have a cable that's capable of 10 times that. The sending and receiving chips (in the source and the TV, respectively) are only capable of 3,840x2,160/30. So you could set your PC to 10,000x10,000-pixel resolution, and even if the cable could support that bandwidth, the video card's HDMI output chip couldn't output it, and the display's HDMI input chip couldn't accept it.

In other words, it's a chain, and all parts of the chain have to have the ability to support all the data. And right now, if the cable is rated high-speed, it can pass all the resolution currently possible with Ultra HD.

The one caveat
Just because a cable is called high-speed, it doesn't mean it actually is. Some cheap HDMI cable manufacturers might just throw the label on a cable that can't actually handle the data or that can't handle the data over long distances. In this case, the cable won't work with 4K (this is true with 1080p as well, btw). This does not mean that all cheap HDMI cables don't work with 4K; it only means that cheap HDMI cable doesn't work with 4K. Get a different brand of HDMI cable, at the same price, and it will likely work.

And, to reiterate the point from all the articles linked above, if it works, that means you're getting 100 percent of the signal. It's either perfect, or it's a failure (as in no image, a flashing image, or the snow shown here). It's not possible for the image to be softer or different-looking from the source. The image can't change because of the cable. It either is or it isn't. There's no "mostly" with HDMI.

The future

Update 6/2015:HDMI 2.0 has arrived.

We were supposed to see HDMI 2.0 by now, but it's been delayed. Chances are it will support much higher frame rates (and resolutions and color depth too, probably). Is it possible these expensive new cables, with their incredible claimed bandwidth, will be able to pass the torrent of data of HDMI 2.0 when it arrives? Yes, but it's also possible they won't. How would we know this early on?

And in reality, it's irrelevant. If you can get a $2 HDMI cable that works now, why would you spend $50 on a cable that will work now, and might work later? Wouldn't it make more sense to wait until 2.0 comes out, and buy a $5 cable that works with the new spec? I'm positive there will be cheap HDMI cables that can handle all the data with HDMI 2.0.

Bottom line
I really didn't want to write another HDMI article, but since we're on the verge of a new marketing misinformation onslaught thanks to 4K, I felt I had to.

You don't need expensive HDMI cables. I don't care where you buy them, but don't waste your money.

Got a question for Geoff? First, check out all the other articles he's written on topics like HDMI cables, LED LCD vs. plasma, Active vs Passive 3D, and more. Still have a question? Send him an e-mail! He won't tell you what TV to buy, but he might use your letter in a future article. You can also send him a message on Twitter: @TechWriterGeoff.


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