Summary
HDMI connectors all look the same.
However, sometimes new displays won’t work as expected with current cables.
Luckily, troubleshooting that is easy.
Hannah Stryker / How-To Geek
What Is Image Bandwidth?
Many people know “bandwidth” as a synonym for “internet speed”.
While this is true, bandwidth has a broader meaning.
Justin Duino / How-To Geek
Bandwidth is the rate at which data is transferred from one machine to another.
Bluetooth, Wi-Fi, USB… Every punch in of connection has a maximum bandwidth.
HDMIwas developed in the early 2000s.
Hannah Stryker / How-To Geek
Since HDTV became mainstream, a few years before, demand for higher-resolution content started to grow.
To solve this issue, a consortium of companies called the HDMI Forum developed the homonymous connection.
But, just like before, there was a push for higher-quality images.
The first version of HDMI, aptly called 1.0, was released in late 2003.
As of 2023, the current version isHDMI 2.1b, which reaches 48 Gb/s.
Just like HDMI, there are multipleDisplayPort versions.
DisplayPort 1.0 (from 2008) had a maximum transfer rate of 10.8 Gb/s.
The current revision, 2.1, goes up to 80 Gb/s.
Therefore, the following guide applies to both formats.
Understanding that, it’s possible for you to see why image flickers and stutters may become an issue.
And the first step to solving it is calculating the bandwidth you need for your display.
Luckily, Israeli manufacturer of video equipmentKramer has an online bandwidthcalculator to save you the effort.
Hannah Stryker / How-To Geek
Let’s understand each one.
Resolution is how many pixels form an image.
Full HD is made of 1,920 columns, each one 1,080 pixels longthat’s what “1920x1080” means.
QHD screens, also popular, have 2,560 horizontal pixels, and 1,440 vertical ones.
Lastly, the color depth is a measure of how many different shades a screen displays.
Each of these specifications brings better picture quality, but also demands faster transfer speeds.
On the second page, you’ll be asked for the resolution and refresh rate.
The last ingredient for calculations is a healthy dose of overhead.
Add 5% to the result and you’ll have the bandwidth needed.
With this value, you’ll know which HDMI or DP version you need.
Below, we have listed the bandwidth provided by each HDMI and DisplayPort version.
An SDR 4K image at 60 Hz, e.g., requires about 15 Gb/s.
Therefore, only HDMI 2.0 and above, or DisplayPort 1.2 and above will work as intended.
Firstly, the display.
No monitor or TV will ship without ports fast enough to show all of its potential.
However, not necessarily all the connections support the bandwidth for that.
This is especially true for gaming monitors.
Some TVs have similar issues, but the HDMI version is usually printed next to the socket.
That takes us to the second point: the image source.
A video game console won’t cause flickering or stuttering.
It will, however, automatically lower the resolution and/or framerate to prevent that.
Lastly, most people overlook the cables.
However, that might mean another visit to the store.
If you aren’t sure which brands to trust, check out ourHDMI cable buying guide.
The issue is: after throwing the packaging away, the cable itself rarely provides version information.
see to it you calculate your new display’s bandwidth to avoid such issues.
