Which is Better for LED Video Walls: DisplayPort or HDMI?

I. Understanding DisplayPort and HDMI

II. Comparison Chart of DP and HDMI

III. Choosing the Right Option Based on Application

From home theater enthusiasts to computer gurus, you won’t find many electronics buffs who don’t applaud the advent of HDMI (High Definition Multimedia Interface) connectors. In the days of analog audio and video, the end user was forced to send these signals separately to video displays and audio equipment, with video typically transferred via component connections and audio sent through multiple RCA cables. When digital audio and video arrived, hobbyists and professionals alike were able to connect devices in different ways, including through DVI, SPIDIF, coaxial and, finally, HDMI, the latter of which promised a new era of connection flexibility and installation ease.

And, make good on that promise HDMI did – indeed, finally there was a connection type that could pass all manner of audio and video signals over one cable, rendering home theater and commercial installation projects a proverbial cinch to complete while eliminating the proverbial rat’s nest of wiring previously associated with large installs. From A/V receivers and satellite/cable boxes to Ultra HD televisions, projectors and beyond, HDMI was often dubbed the best thing to happen to the connection cable world.

Yet as the HDMI spec evolved, so did its application blueprint, to the point that we’re now looking at which is better DP or HDMI for LED video walls, which is the topic of discussion for this article. We’ll be focusing on understanding both these choices, how to choose the right one for different applications, the difference between resolution and refresh rate and more.

I. Understanding DisplayPort and HDMI

HDMI and DisplayPort are two standards for connecting devices such as computers, laptops and game consoles to televisions, monitors and projection systems, and each come with advantages and disadvantages. While HDMI, as we suggested above, is the reigning king of compatibility and convenience, power users often cite things that are more appealing about DisplayPort.

These competing display connection standards transmit – as we also hinted at in the introduction portion – both video and audio signals over a single male/male cable to respective female ports on the source device/display, albeit with different “pin” patterns. They’re both physically sturdy and easy to connect, boasting backward and forward compatibility; HDMI uses standard and mini-connectors while DisplayPort uses DisplayPort, Thunderbolt/Mini DisplayPort and USB 3 connections.

DisplayPort wins the spec war over HDMI, even though not all ports and cables are the same for both, given that they have several version revisions. Let’s now take a brief look at some technical details for these connectors.

HDMI boasts four revision groups as of 2021:

• 1.0-1.2: 4.95 Gbps of data bandwidth that supports 1080p at 60 Hz

• 1.3-1.4: 10.2 Gbps of data bandwidth that supports 1080p up to 144 Hz and 4K at 30 Hz

• 2.0: 18.0 Gbps of data bandwidth that supports 1080p at 240 Hz, 4K at 60 Hz and HDR

• 2.1: 48 Gbps of data bandwidth that supports 4K at 144 Hz and 8K at 30Hz

DisplayPort boasts five revision groups as of 2021:

• 1.0-1.1: 10.8 Gbps of data bandwidth that supports 1080p at 144 Hz and 4K at 30 Hz

• 1.2: 21.6 Gbps of data bandwidth that supports 1080p at 240 Hz, 4K at 75 Hz, and 5K at 30 Hz

• 1.3: 32.4 Gbps of data bandwidth that supports 1080p at 360 Hz, 4K at 120 Hz, 5K at 60 Hz and 8K at 30 Hz

• 1.4: 32.4 Gbps of data bandwidth that supports up to 8K at 60 Hz and HDR

• 2: 80.0 Gbps of data bandwidth that supports up to 16K at 60 Hz with HDR on and up to 10K with HDR off at 80 Hz

Another important factor to note before we move on is that an HDMI port can only connect to one screen, while DisplayPort features Multi-Stream Transport (MST) for multiple screens and daisy-chaining. Further, DisplayPort can connect to four screens at once – though because DisplayPort splits bandwidth between the displays, results will vary depending on the setup.

II. Comparison Chart of DP and HDMI

III. Choosing the Right Option Based on Application

The market availability of HDMI 2.1 – the latest spec – compared to DisplayPort 1.4 is a statement of its use case, market share and how likely you are to find it in retail stores. DisplayPort is readily obtainable in the market, but is limited to workstations and gaming for the most part; this is why it has been the ideal data transmission cable among gamers for years.

On the other hand, HDMI 2.1 can be leveraged for different use cases and settings, though it is also popular amongst gamers, workers and individuals running high-resolution monitors and televisions – including LED video walls.

III-A. Resolution and Refresh Rate

Knowing the type of resolution your preferred cable supports is an important factor that needs to be considered before purchasing any, especially if you already have a display technology you intend to utilize. To put it more succinctly, DisplayPort 1.4 supports 4K resolution at 120Hz and 8K resolution at 60Hz, while HDMI 2.1 supports these resolutions at better refresh rates with a maximum resolution of 10K.

When we speak of “refresh rate,” we’re referring to how often a display device shows an image within a time frame of one second. This figure is measured in “hertz” (Hz) and determines whether there will be lag and increased latency in a video output or not; for example, if a transmission tech boasts a refresh rate of 60Hz, it means it draws or displays 60 images every second. In the HDMI vs. DisplayPort debate, both have impressive rates, but as the resolution under consideration increases, the refresh rates drop significantly. DisplayPort max refresh rates exist in 1080p resolution, and as the resolution gets higher to 1440p, the refresh rate drops to 144Hz and to 120Hz for 2K; conversely, this is quite different from HDMI 2.1, which boasts an overall maximum refresh rate of 240Hz. The difference here is that HDMI 1440p max refresh rate is the same as 1080p and 2K, which is 240Hz, yet the HDMI 4K max refresh rate stands at 120Hz.

III-B. Content Source and Cable Length

The DisplayPort standard pegs optimum data transmission at approximately three (3) meters of cable length, however, the cable can be extended up to 20 meters while allowing, at the very least, a high-definition resolution. The HDMI standard does not specify exact dimensions and capabilities in terms of cable length, though generally they’re shorter than DisplayPort cables and normally come in two (2)-meter lengths for optimum performance.

DisplayPort may not be commonly found on mainstream devices such as gaming consoles, monitors, graphics cards and televisions, but its connectors are common in devices priced higher than average, such as gaming monitors and high-end graphics cards. HDMI connectors come in four sizes – standard, mini, micro and automotive – with each serving a unique purpose; standard HDMI connectors or Type A HDMI connectors are typically used by corporations and personal users. They connect source devices such as gaming consoles and Blu-ray/Ultra HD Blu-ray players to monitors, televisions and projectors.

III-C. Additional Features

DisplayPort connectors have 20 pins, with two sizes available, the standard DisplayPort and a smaller alternative made by Apple called Mini DisplayPort; the latter is the same port as the Thunderbolt variant. While HDMI connectors are typically comprised of 19 pins, the lesser-known Type B variant boasts 29 pins and is used for dual-link applications, whereas the Type E has a locking tab to keep the cable from vibrating loose in automotive applications.

III-D. Compatibility

A question we often hear is: “Can I connect a DisplayPort to an HDMI monitor?” and our answer is always the same – yes and no.

For the record, a DisplayPort signal is not compatible with HDMI, but if the DisplayPort output is a dual mode variant, it has the ability to recognize and adjust the signal to HDMI when a passive adapter cable is connected. From our experience, sometimes this will work and sometimes it won’t; if the DisplayPort graphics card is only a single mode variant, then you must use an active adapter or converter.

Both HDMI and DisplayPort technologies have improved dramatically in recent years, and that shows no signs of slowing down. Between HDMI 2.1 nearly tripling the data rate and bandwidth of version 2.0 – and doubling the capabilities of DisplayPort 1.4 – and expanding support for other visual enhancements like dynamic forms of HDR (Dolby Vision/HDR10+) for richer colors, variable refresh rates for smoother gaming, reduced latency for gaming, faster source media switching and enhanced audio, the future is definitely in the hands of these pin-oriented connectors.