What Is DP 2.1? DisplayPort 2.1 Explained

DisplayPort 2.1 or DP 2.1 is the current version of DisplayPort, a video connectivity interface introduced by the Video Electronics Standards Association (VESA). VESA released the earliest DisplayPort version, DisplayPort 1.0, in early 2006 to replace older video interfaces like VGA and DVI, which limited the user experience with lower resolutions and refresh rates.

Over the years, VESA has upgraded the specifications and capabilities of DisplayPort. To put things in perspective, where DisplayPort 1.0 typically supported 1440p@60Hz in 2006, DisplayPort 2.1 (the newest version) supports up to 16K@60Hz (DSC). These top-notch specifications allow users to connect multiple high-resolution displays, ideal for experiencing immersive gaming or performing graphics-intensive tasks like image and video editing.

Although improved resolutions and faster refresh rates are DP 2.1’s most significant features, it has plenty more to offer by way of convenience and utility. Moreover, DisplayPort 2.1 provides multiple transmission modes, making it vital to understand their capabilities and decide which one to adopt.

DisplayPort 2.1: UHBR10 and UHBR20

Since its inception, DisplayPort’s internal architecture employs four data lanes to connect a host and a peripheral. The earliest DisplayPort version offered a total bandwidth of 10.80 Gbps across four lanes, and VESA classified the transmission mode as HBR (High Bit Rate). With time and growing demand for high-resolution displays, VESA upgraded the bandwidth over the years to offer 17.28 Gbps and 25.92 Gbps with HBR2 (DisplayPort 1.2) and HBR3 (DisplayPort 1.4/1.4a) transmission modes, ensuring support for multiple displays and high-resolution screens.

Transmission Mode	Certification	Total Bandwidth
RBR	DP 40/DP 80	6.48 Gbps
HBR	DP 40/DP 80	10.8 Gbps
HBR2	DP 40/DP 80	21.6 Gbps
HBR3	DP 40/DP 80	32.5 Gbps
UHBR 10	DP 40	40 Gbps
UHBR 13.5	DP 80	54 Gbps
UHBR 20	DP 80	80 Gbps

DisplayPort 2.1 offers a total bandwidth between 40 Gbps and 80 Gbps, depending on its transmission mode. VESA introduced three new transmission modes to support higher bandwidths with the release of DisplayPort 2.0: UHBR 10, UHBR 13.5, and UHBR 20. While the acronym UHBR signifies an “Ultra-high Bit Rate,” the numbers represent the bandwidth of each data lane.

Note: UHBR 13.5-rated cables and devices are virtually nonexistent. DisplayPort 2.1 mainly uses UHBR 10 and UHBR 20 DisplayPort-certified (discussed in the next section) devices.

However, the increased bandwidth is one of many reasons DP 2.1 supports video signals up to 16K@60Hz (using Digital Stream Compression or DSC). Of course, it contributes significantly to supporting higher resolutions, but a lot depends on the reduced signaling overheads (discussed later), which play an equally significant role.

These high bandwidths (and bit rates) make DP 2.1 the first standard to offer 8K@60Hz with uncompressed video 4:4:4 full-color depth and 30 bits per pixel HDR10 support. Simply put, DP 2.1 offers never-before-seen visuals with stunning color accuracy (per pixel) and incredible clarity.

Interestingly, DisplayPort 2.1 (UHBR 20) also supports 16K@60Hz video with HDR and 10-bit color depth. While finding such high-resolution content is a challenge, such specifications are more aligned with the future needs of content creators working in video editing roles.

Meanwhile, a more practical application of these high-end specifications would be to power high-performance gaming monitors, as DP 2.1 can generate up to 900Hz refresh rate for 1080p frames.

DisplayPort Certification

For most users, it’s confusing enough to differentiate between DisplayPort versions even without considering transmission modes. It’s hard to keep track of the number of lanes, per lane bandwidth, total bandwidth, and whatnot.

So, to simplify this, VESA has developed a simple, straightforward identification that labels DisplayPort cable based on total bandwidth. DisplayPort cables are labeled DP40 or DP80, depending on the total bandwidth. Thus, you don’t need to consider the version numbers or UHBR types while buying a DisplayPort device (or cable).

DisplayPort 2.1’s 128b/132b Encoding And Its Advantage

From DisplayPort 1.0 up to DisplayPort 1.4/1.4a, VESA used an 8b/10b encoding scheme for video signals. While it was a great starting point and is a vital part of the success of DisplayPort, it is a highly inefficient encoding scheme because of its high signaling overheads.

The 8b/10b encoding scheme uses two encoding bits for every 8-bit piece of data, giving it a 20% overhead. This means that if the DisplayPort interface has a total bandwidth of 10.8 Gbps (DisplayPort 1.0/1.1), the usable bandwidth was 20% lesser at 8.64 Gbps, making it a highly inefficient video interface.

DisplayPort 2.0 (and DP 2.1) removed this inefficiency using a 128b/132b encoding scheme that uses only four bits to encode a 128-bit payload, reducing overheads to a little over 3% of the signaling bandwidth. Not only did it minimize wastage, but the new signaling scheme streamlined the video interface and maximized bandwidth availability.

With reduced overheads, DP 2.1 can carry more data in a clock cycle, enhancing overall data throughput. As a result, your video signals have more pixel information, which facilitates the use of high-resolution monitors.

Moreover, the lower overheads combined with higher bandwidths and daisy chaining enable you to connect multiple high-resolution monitors, making it easier to set up a streamlined workstation for multitasking.

Video Specifications Of DisplayPort 2.1

DisplayPort 2.1 supports Digital Stream Compression, VESA’s lossless video compression algorithm, which helps optimize and stream high-resolution video signals. Thus, the DisplayPort interface can support the following video specifications depending on whether the signal uses DSC.

Number of Monitors	With DSC	Without DSC
Triple Monitor	10K@60Hz	4K@90Hz
Dual Monitor	8K@120Hz	4K@144Hz
Single Monitor	16K@60Hz	10K@60Hz
Using 2-lane USB-C DP Alt Mode	Three 4K@144Hz	Three QHD (2560×1440) @120Hz One 8K@30Hz

DisplayPort 2.1 Vs. HDMI 2.1: Which Is Better?

While HDMI and DisplayPort are the two most popular audio-video interfaces on the market, their specifications show notable differences. For instance, HDMI 2.1 offers 48 Gbps bandwidth as opposed to DisplayPort 2.1, which offers between 40Gbps and 80 Gbps depending on the transmission mode (or certification).

Consequently, DisplayPort 2.1 offers higher resolution and refresh rates than HDMI 2.1. While DisplayPort 2.1 offers 16K@60Hz (with DSC), the best HDMI 2.1 offer is 10K@120Hz (with DSC), making DisplayPort the go-to standard when you need higher resolutions for graphics and video editing tasks.

DisplayPort allows you to daisy chain monitors, making it easy to set up a multi-monitor workstation using DisplayPort MST (Multi-stream Transport). HDMI 2.1 doesn’t have this feature, making setting up a multi-monitor workstation challenging.

Nevertheless, both standards find pride of place in the market. While HDMI has greater acceptance among television sets and single-screen typical office workstation setups, gamers, and content creators prefer DisplayPort because it supports high-end video quality and multitasking features.

Conclusion

Presently (in late 2023), DisplayPort 2.1 is the best interface for high-end video quality that requires the highest resolutions and fastest refresh rates. It is still relatively new, so compatible monitors and accessories are expensive.

And as with all the latest technology, you are expected to bear the early adopter’s fee. So, while competitive gamers and professional content creators may be okay with the price, less demanding users will prefer older DisplayPort (or HDMI) versions as they offer excellent image quality at affordable prices.