You Are Probably Using the Wrong HDMI Cord
Alex Cranz (via John Gordon):
The first thing to understand is that the HDMI cable is not like the component, composite, or S-video cables you might have plugged into your TV in years past. All that mattered with those cables is that they were well made and had the right plugs. HDMI cables are more like USB or ethernet cables, however. There are different versions that look identical on the outside, but can grossly affect how much data you’re moving from point A to point B. You know how that old USB 2.0 cord slows down your external hard drive compared to a USB 3.0? HDMI is subject to the same kind of limitation—specifically, bandwidth.
There are, to date, seven different HDMI versions, starting with 1.0, which was introduced back in 2002, and currently ending with 2.1, which was only announced back in November of 2017.
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At this point, you might think you cracked the code, as if you could just go out, find an HDMI 2.0 or 2.1 cable, plug it in, and you’re good to go. Unfortunately, in 2012 HDMI pulled a truly bonehead move and essentially forbid anyone from actually saying what standards their cables support.
Update (2018-06-23): Ashley Bischoff:
And I gather that compatibility is less of a concern than the author makes it out to be.
This comment from spoonTRex seems to sum things up decently.
There may be 13 different HDMI standards (see also https://en.wikipedia.org/wiki/HDMI#Version_comparison), but there are only four HDMI cable types: standard (4.95 Gbit/s), high-speed (10.2 Gbit/s), premium (18 Gbit/s) and ultra (48 Gbit/s). The differences are entirely a matter of how much bandwidth they can reliably deliver and have nothing at all to do with HDMI version numbers.
This is because every HDMI version defines a large collection of features. Some features require more bandwidth than others. If you have a new "HDMI 2.1" device but it is only using those features that require 10.2 Gbit/s or less, then you don't need an "ultra" cable. The only people who will require that are those using high-end HDMI 2.1 features (like 8K video) that are not supported by any consumer devices at this time.
You really don't want TV salespeople telling customers that they need an "HDMI 2.1 cable" just because their Blu-Ray player or computer has an HDMI 2.1 port on it. These deceptive sales practices were taking place all the time a few years ago when there were only two cable types (standard and high-speed) with high-speed costing much more than standard. People were convinced that they needed expensive cables when they really didn't and the sales people were raking in the profits.
The only complaint I've had with HDMI marketing is the fact that the certification doesn't have to be (and usually isn't) printed on the cable, so it can be very easy to forget what a random cable in a box is and isn't capable of.