The DisplayPort interface version 2.1 allows for a maximum bandwidth of up to 80 Gbps, depending on the transmission mode. It’s backward compatible with the previous DisplayPort standards, and supports DSC and MST as a baseline.
With newer monitors getting higher and higher refresh rates and resolutions, and newer graphics cards and CPUs getting a lot faster, we’re going to need a video interface that’ll be able to keep up with all that – preferably without compressions!
This is where DisplayPort 2.1 comes in.
Note that the newer DisplayPort 2.1 standard succeeds DisplayPort 2.0. So, all previous DP 2.0 devices are now also DP 2.1 certified.
DisplayPort 2.1 Bandwidth
Thanks to DSC (Display Stream Compression), which is visually lossless, DisplayPort 1.4 and HDMI 2.1 can already support very high resolutions and refresh rates, so when exactly will we be able to take full advantage of DisplayPort 2.1?
DisplayPort 2.1 can triple the maximum bandwidth of DisplayPort 1.4, depending on its transmission mode.
DP 1.4 with its highest HBR3 (High Bit Rate) transmission mode has a maximum bandwidth of 32.40 Gbps, or 25.92 Gbps data rate.
DP 2.1 has three UHBR (Ultra High Bit Rate) transmission modes:
|Maximum Data Rate|
|UHBR10||40 Gbps||38.69 Gbps|
|UHBR13.5||54 Gbps||52.22 Gbps|
|UHBR20||80 Gbps||77.37 Gbps|
As you can see, DP 2.1 also has higher efficiency regarding the maximum bandwidth capacity and actual data rate thanks to its 128b/323b encoding:
- DP 1.4: 32.40 Gbps, 25.92 Gbps data rate – 80% efficiency
- DP 2.1: 80 Gbps, 77.73 Gbps data rate – 96.7% efficiency
In comparison, HDMI 2.1 has a maximum bandwidth of 48 Gbps or 42.6 Gbps data rate.
So, unlike HDMI 2.1, DP 2.1 devices with UHBR20 could support 4K 240Hz, 8K 60Hz, 1440p 500Hz and 10-bit color depth – without relying on DSC. With DSC, DP 2.1 can support significantly higher resolutions, such as 16K 60Hz!
DisplayPort 2.1 Compatibility
DisplayPort 2.1 is backward compatible with DP 1.2 and DP 1.4. So, you can connect a GPU with DP 1.4, for instance, to a display with DP 2.1, but you’ll be limited to DP 1.4 bandwidth.
In order for a device to have ‘DisplayPort 2.1’, it must support DSC and at least one of the following three features:
- LTTRPs (Link-Training Tunable PHY Repeaters) for ensuring signal integrity
MST (Multi-Stream Transport) used for daisy-chaining is now a baseline of DP 2.1.
This means that a DP 2.1 device might not necessarily support UHBR and therefore be limited to a bandwidth of HBR3, which can be very misleading. So, once we finally see DP 2.1 devices, you’ll have to pay attention to their transmission modes, which will hopefully be clearly specified by manufacturers.
Sadly, this is also the case with HDMI 2.1 as it has different fixed rate link (FRL) rates, ranging from FRL1 with 9 Gbps to FRL6 with 48 Gbps.
Even the DisplayPort 1.4 specification can be misleading since some monitor manufacturers advertise their displays to have DP 1.4 as they have HDR support (which DP 1.2 does not) – even though they’re limited to HBR2 bandwidth (21.6 Gbps or 17.28 Gbps data rate).
In the end, you’d get a 1440p 144Hz+ display that’s limited to 120Hz with 10-bit color depth even though it’s specified to have DP 1.4, such was the case with the Acer XV272UP. Luckily, some manufacturers label these displays as ‘DP 1.2 + HDR.’
DisplayPort 2.1 Cables
In order to take advantage of DisplayPort 2.1, you’ll need either a DisplayPort cable labeled as ‘DP40’ with 40 Gbps for UHBR10 or a ‘DP80’ cable with 80 Gbps for UHBR13.5 and UHBR20 devices.
The DisplayPort logo for DP 2.1 devices remains the same as the older ones, so you’ll have to rely on the specified bandwidth capacity.
Another thing to note is that, just like with the previous DisplayPort standards, there’s no difference between full-sized DisplayPort and mini-DisplayPort interfaces, besides the size of the physical connector.
DisplayPort 2.1 GPUs and Displays
Unlike NVIDIA’s 4000-series RTX GPUs, AMD’s RX 7900 XT and RX 7900 XTX graphics cards will support DisplayPort 2.1 with UHBR13.5 (54 Gbps).
AMD also revealed that the next version of the Samsung Odyssey Neo G9 will feature an ‘8K ultrawide’ resolution (most likely 7680×2160) that’ll be run by DisplayPort 2.1.
We tried to keep this article short with the most important information. VESA is yet to reveal a list of all optional features, but you can find more technical information on their website.
Since DP 1.4 with DSC can already deliver very high resolutions and refresh rates (4K 240Hz 10-bit, 1440p 500Hz+ 10-bit, etc.), there’s no need to ponder about DP 2.1 just yet – although we’ve seen people not wanting to upgrade their GPUs or monitors until DP 2.1 becomes available.
Of course, it wouldn’t be a VESA certification if there weren’t any room for potential misinformation and confusion since DP 2.1 can basically have the same maximum bandwidth as DP 1.4 if it doesn’t support the optional UHBR feature. So, people will have to pay attention to the (hopefully) specified DP 2.1 maximum bandwidth and data rate by the display manufacturer.