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DisplayPort 2.1 became a much bigger talking point than expected when AMD unveiled its upcoming RX 7900 XTX and RX 7900 XT GPUs. It’s the latest DisplayPort standard, a revision to the 2.0 specification released in 2019, and it’s a natural inclusion for next-gen GPUs. There’s just one problem – Nvidia’s behemoth RTX 4090 still uses DisplayPort 1.4a.
Although the 1.4a spec is still more than enough for most people, the inclusion of DisplayPort 2.1 gives AMD an edge this generation. No, I’m not here to sell you on 8K gaming – in some parts of the world, 8K may not even be possible – but for a host of competitive gamers and VR enthusiasts, DisplayPort 2.1 could mark a major shift.
An update four years in the making
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 market supporting a new standard, but DisplayPort 2.1 isn’t that new. It’s a refresh to DisplayPort 2.0, which launched in 2019, and a massive improvement over DisplayPort 1.4, which we’ve seen since 2016.
Like any new connection, it’s all about bandwidth. DisplayPort 1.4a, which you’ll find on all recent graphics cards except the Intel Arc A770 and A750, as well as AMD’s upcoming RX 7900 XTX, tops out at 25.92 Gbps of maximum data rate. DisplayPort 2.1 goes up to 77.37Gbps (theoretical bandwidth is higher if you see different numbers, but this is the actual data rate possible across the cable). If you run some, admittedly complicated, maths, you’ll find that the required data rate for 4K at 120Hz with HDR on is 32.27Gbps – higher than what DisplayPort 1.4a is capable of.
Displays like the Samsung Odyssey Neo G8 support 4K at 240Hz with only 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 mathematically lossless, but it is visually lossless. And it can reduce the required data by up to a 3:1 ratio, taking that 32.27Gbps number down to 10.76Gbps. That’s great, and DSC is the only reason DisplayPort 1.4a hasn’t already been kicked to the curb.
The problem is that the limitations of DisplayPort 1.4a are starting to show, even with DSC enabled. A theoretical 4K display at 360Hz wouldn’t be able to run at its full refresh rate, even with DSC compression at 3:1 (the required data rate is 36.54Gbps, in case you were wondering). And higher color depths for HDR add even more bandwidth requirements, as do higher refresh rates and resolutions.
A 4K 360Hz display may sound crazy now, but we have hardware capable of driving such a display. AMD claims 295 fps at 4K in Apex Legends and 355 fps in Overwatch 2. In addition, the RTX 4090 can push over 300 fps at 4K in Rainbow Six Siege, and the frame generation capabilities of DLSS 3 and the upcoming FSR 3 will certainly challenge the position of the 4K at 240Hz maximum that we currently have on gaming monitors.
Most people don’t need that extra refresh rate, 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
Strangely, we don’t expect hardware to take advantage of monitors. We are waiting on screens to show new hardware. Samsung already teased its “8K” Odyssey Neo G9 for CES this year – for the record, it’s not true 8K, but rather two 4K screens side by side in the ratio of 32: 9 – and we expect to see at least . a handful of 8K gaming monitors to be shown at the show according to Samsung’s display.
That screen is also a good touchstone. Assuming Samsung wants to keep a 240Hz refresh rate like the current version has, you’re looking at a data rate over 45Gbps with HDR on (36.19Gbps with HDR off), and that’s with 3:1 compression. This is all theoretical for now, we have 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 them due to its DisplayPort 1.4a connection (at least at full refresh). rate, DisplayPort is backwards compatible).
There’s also no need to limit this conversation to 8K or super high refresh rates at 4K. OLED TVs masquerading as gaming monitors are becoming increasingly popular, and they could see huge benefits from 5K and 6K resolutions. As I saw with LG’s UltraGear 48 OLED, the pixel density needs to be higher for such a large screen so close to your face. DisplayPort 1.4a can drive 5K and 6K with DSC, but not at refresh rates above 120Hz and not at higher HDR color depths.
That data rate limit also appears in VR. The Pimax Crystal, which is currently a Kickstarter campaign, should claim about 29Gbps of data with DSC at 3:1 according to the specifications. That’s what DisplayPort 1.4a is capable of, but it reaches the limit.
From large form factor displays to VR headsets to higher refresh rates at 4K, DisplayPort 1.4a is starting to reach its full capacity. If both AMD and Nvidia stuck with DisplayPort 1.4a, it wouldn’t be a big deal. Screen manufacturers would adapt to the capabilities of what is currently in the market. But AMD is opening the doors with its new GPUs.
An important distinction, but not a selling point
Of all the things to base a purchasing decision on, the DisplayPort standard should be way down on that list. We have yet to see how AMD’s new GPUs perform, what features like FidelityFX Super Resolution (FSR) 3.0 will bring, and if bypassing the barrier gaming screens now even makes sense.
However, that’s where the trend is going, and the difference between DisplayPort 1.4a and 2.1 may become more important much faster than we anticipated – at least for an advanced class of gamers who want to experiment with cutting-edge technology.
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