DisplayPort 2.1 was a bigger talking point than expected when AMD revealed its upcoming RX 7900 XTX and RX 7900 XT GPUs. It’s the latest standard from DisplayPort, a revision of the 2.0 spec released in 2019, and it’s a natural fit for next-generation GPUs. There’s just one problem – Nvidia’s behemoth RTX 4090 still uses DisplayPort 1.4a.
While the 1.4a spec is still more than enough for most people, the inclusion of DisplayPort 2.1 gives AMD an advantage this generation. No, I’m not here to sell you on 8K gaming – in some parts of the world, 8K may not be possible – but for the competitive gamer crowd and VR enthusiasts, DisplayPort 2.1 could mark a big change.
A four-year review is conducted
VESA, the company that defines and certifies the DisplayPort standard, released DisplayPort 2.1 in October 2022. It usually takes years for products to make their way to the market that support the new standard, but DisplayPort 2.1 isn’t all that new. It’s a refresh from DisplayPort 2.0, which was introduced in 2019, and a big improvement over DisplayPort 1.4 that we’ve seen since 2016.
As with any new connection, it’s all about bandwidth. DisplayPort 1.4a, which you’ll find on all recent graphics cards short of the Intel Arc A770 and A750, and AMD’s upcoming RX 7900 XTX, tops out at 25.92 Gbps of maximum data rate. DisplayPort 2.1 goes up to 77.37Gbps (the theoretical bandwidth is higher, in case you see different numbers, but this is the actual data rate possible across the cable). If you run the math, which is admittedly complicated, you’ll find that the required data rate for 4K at 120Hz with HDR on is 32.27Gbps – more than what DisplayPort 1.4a is capable of.
Monitors like the Samsung Odyssey Neo G8 only support 4K at 240Hz with DisplayPort 1.4a, so what gives? DisplayPort (and HDMI now) uses Display Stream Compression (DSC) to reduce the amount of data required. DSC is not statistically lost, but it appears to be. It can also reduce the data required by a ratio of up to 3:1, taking that 32.27Gbps number down to 10.76Gbps. That’s great, and DSC is the only reason DisplayPort 1.4a can be kicked to the curb.
The problem is that the limitations of DisplayPort 1.4a are starting to increase, even with DSC enabled. A 4K 360Hz theater monitor won’t be able to run at its full refresh rate, even with DSC compression at 3:1 (required data rate is 36.54Gbps, in case you were wondering). And HDR’s higher color depth adds more bandwidth requirements, as do higher refresh rates and resolutions.
A 4K 360Hz monitor might sound crazy now, but we have hardware capable of driving such a display. AMD claims 295 fps at 4K in Legends of the Apex and 355fps in Overwatch 2. Furthermore, the RTX 4090 can push over 300 fps in 4K in Rainbow Six Siege, and the ability to produce DLSS 3 frames and the upcoming FSR 3 is sure to challenge the position of 4K at 240Hz maximum that we currently have in gaming monitors.
Most people don’t need that extra amount of refresh, but let’s be honest; most people don’t need to spend $1,600 (or even $1,000) on a GPU, either.
We have the hardware
Ironically, we are no longer waiting for the hardware to take advantage of the monitors. We are waiting for the monitor to show the new hardware. Samsung has already teased its “8K” Odyssey Neo G9 for CES this year – for the record, it’s not true 8K, but two 4K displays combined with an aspect ratio of 32:9 – and we expect to see at least. a number of 8K gaming monitors will be on display alongside Samsung’s display.
That display is a great touchstone, too. Assuming Samsung wants to keep the 240Hz refresh rate as the current version has, you’re looking at a data rate of over 45Gbps with HDR on (36.19Gbps HDR off), and that’s with 3:1 compression. This is all a theory at the moment, we need to wait until we see this display and other 8K options, but the numbers suggest that the RTX 4090 may not be able to drive itself due to its DisplayPort 1.4a connection (at least to fully update the standard, DisplayPort is backwards compatible) .
There’s no need to limit this discussion to 8K or the much higher refresh rates of 4K, either. OLED TVs that double as gaming monitors are becoming increasingly popular, and could see big gains in 5K and 6K resolutions. As I saw with LG’s UltraGear 48 OLED, the pixel density needs to be high for such a large screen that is close to your face. DisplayPort 1.4a can drive 5K and 6K with DSC, but not at refresh rates above 120Hz and not at high HDR color depth.
That amount of data compression is evident in VR, too. The Pimax Crystal, which is currently on Kickstarter campaign, should require around 29Gbps of data with DSC at 3:1 based on the specs. That’s within what DisplayPort 1.4a is capable of, but it’s reaching a limit.
From large form factor displays to VR headsets to high refresh rates in 4K, DisplayPort 1.4a is starting to reach its full potential. If both AMD and Nvidia stuck with DisplayPort 1.4a, that wouldn’t be a big deal. Show producers will be familiar with the strengths of what is currently on the market. But AMD is opening the floodgates with its new GPUs.
An important difference, but not a selling point
Of all the things you can base a buying decision on, DisplayPort should rank very low on that list. We still need to see how AMD’s new GPUs perform, what features such as FidelityFX Super Resolution (FSR) 3.0 will bring, and if pushing past the current barrier gaming monitors makes sense.
This is where the trend is headed, however, and the difference between DisplayPort 1.4a and 2.1 may be related more quickly than we expected – at least in the category of high-end gamers who want to try the bleeding edge technology.