HDMI 2.1 brings 8K, 10K resolution and variable refresh rates

The masterminds behind everyone’s favorite HDMI connector announced a huge upgrade to the HDMI spec in the form of HDMI 2.1. For those unaware, most of the 1080p HDTV era was fueled with HDMI 1.4 displays, providing enough bandwidth to support 1080p content at 60 frames per second, or 4K content at 30 frames per second in most cases. This specification was upgraded to HDMI 2.0 spec a few years ago to support 4K resolution at 60hz, and serves as the backbone of every modern 4K display today.

The HDMI forum listed the following improvements with HDMI 2.1:

  • Higher Video Resolutions support a range of higher resolutions and faster refresh rates including 8K60Hz and 4K120Hz for immersive viewing and smooth fast-action detail.
  • Dynamic HDR ensures every moment of a video is displayed at its ideal values for depth, detail, brightness, contrast, and wider color gamuts—on a scene-by-scene or even a frame-by-frame basis.
  • 48G cables enable up to 48Gbps bandwidth for uncompressed HDMI 2.1 feature support including 8K video with HDR. The cable is backwards compatible with earlier versions of the HDMI Specification and can be used with existing HDMI devices.
  • eARC supports the most advanced audio formats such as object-based audio, and enables advanced audio signal control capabilities including device auto-detect.
  • Game Mode VRR features variable refresh rate, which enables a 3D graphics processor to display the image at the moment it is rendered for more fluid and better detailed gameplay, and for reducing or eliminating lag, stutter, and frame tearing.

With HDMI 2.1, this resolution cap is more than doubled by providing 8K and 10K resolution support. It also increases the refresh rate ceiling of 4K from 60hz to 120hz, allowing gamers to finally experience 120 frames per second gameplay at 4K resolution. To take advantage of these extremely high resolutions, a new 48Gbps cable will be required, as previous generation cables cap out at 18Gbps. This won’t be necessary if you’re planning to stick to current resolutions though. HDR support has also been expanded with Dynamic HDR, which will allow content creators to dynamically adjust HDR image quality on a frame-by-frame basis.

Perhaps the most exciting development with HDMI 2.1 is the support for Game Mode VRR, which brings variable refresh rate technology into HDMI spec! For those unaware, variable refresh rate technology was made to combat the shortcomings of V-Sync, which include stutters and increased input lag. Disabling V-Sync would eliminate input lag problems, however it would result in a noticeable amount of screen tearing, which is highly distracting to a gamer. NVIDIA G-Sync and AMD FreeSync were released to combat these shortcomings and provide a much better gaming experience. The downside to this technology is that your whole chain of equipment has to be tailored to a specific vendor: either you invest in a NVIDIA GPU + G-Sync monitor or Radeon GPU + FreeSync monitor.

With Game Mode VRR, this specification could likely result in the PlayStation 4 and Xbox One receiving variable refresh rate support, which is a giant leap for console gaming! While these consoles have recently been refreshed to support HDMI 2.0 specification, it’s possible that Game Mode VRR could be enabled via a firmware update, though this is only speculation at this point. The addition of Game Mode VRR to HDMI spec could also result in HDTV manufacturers to adopt variable refresh rate support, which has been my only complaint with the technology so far. While it’s amazing, I wish that I wasn’t tethered to a 27-34-inch display, and would much rather game on something much larger. With HDMI 2.1, that may soon become a reality. HDMI 2.1 is scheduled to be released in Q2 2017.

About the author

Adeel Soomro

Adeel Soomro

Adeel Soomro, also known as "Four Wude", has been a competitive Street Fighter 4 player since 2008. Using his extensive gaming experience on a casual and professional level, he aims to spread the awareness of input lag existing in today's displays. Having tested over 300 displays for input lag, he hopes that DisplayLag will aid gamers around the world when purchasing the best HDTV or monitor for gaming.


  • slight correction, FreeSync is not technically tied to AMD at all.
    FreeSync is just what they call their own implementation of Adaptive-Sync, the VESA standard of VRR in DisplayPort which is what the monitors actually support.
    since it is a standard Nvidia could also technically benefit from it with just a driver update (although for whatever reason they don’t).

    • Freesynch was developed by AMD but being a consumer friendly company , it made it available to everyone and thus monitor manufactures can implement it without paying any fee while nVidia has the G-synch which is essentiallly the same technology but with timings and frequencies of nVidia video cards and it is proprietary and nVidia charges a hefty amount of fee from the display manufacturers if they want to implement it in their products.

  • why is it the HDMI guys only think one little step ahead, for years they only supported 4k@60, now ohhh we’ll give you 4k@120

    why not actually make a standard that supports 16K@120 and not have to replace cables and everything all the time, might also allow TV’s to offer 4k@120 long ago when it was possible rather than waiting for “yet another standard upgrade”

    better yet just go optical that has no real limit.

    • Little correction before I answer your question for the longest time they supported 1080p@60Hz and 4K@30Hz but it became better with HDMI 2.0 , which happened more recently, and the refresh rates doubled i.e. 120 and 60 Hz for 1080p and 4K respectively.

      Well, it has to do with the technology and economics. A cable with 244 Hz @ 8K won’t make any sense if the no videocard and no display can support it. And it will be super expensive so no one will buy it. However, when the market it ready, then it makes more sense to release the next standard.

  • I have a Samsung 4K tv un49ks8000 and in game mode the lag is 20ms, if I use the 2.1 cables, can I expect my lag to reduce and I assume these cables will work with that tv in game mode 1080 @60hz, thanks

    • Hi Scott,
      Using 2.1 cables will more than likely not reduce or change your lag in any way. They will be backward compatible, so you shouldn’t expect your performance to be any worse than it is now.

  • Will these cables improve the lag on my Samsung un49ks8000 tv, or wil they be just like the 2.0 version since my tv is hdmi 2.0

  • Here is a good question for someone of your knowledge level, I play fighting games on ps4 with the Samsung tv which has 20 ms of lag and a response of 18 ms, with that low lag would a monitor help at all, which has a lag of 10 ms, I know the average person response is between 180 and 320 ms, most individuals is around 270 ms, I personall thinks it would not matter, I could see if a tv had 80 ms and above, that it could help, thanks scott

    • For me personally, it does matter. There is still roughly a 1 frame difference going to a fast TV, but it takes quite a bit of practice to even notice it. For most players, there isn’t a significant difference if you’re happy with the TV overall. I still play on TVs with this input lag and am able to adjust very quickly.

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