While AMD wasn’t the first GPU vendor to implement a system for variable refresh, the company has made up for lost time with zeal. Since demonstrating their FreeSync proof-of-concept laptop demo back at CES 2014, AMD has since been able to get the necessary signaling and refresh technology implemented into the DisplayPort standard as an optional annex of 1.2a, more commonly known DisplayPort Adaptive-Sync. With DPAS implemented into monitors, AMD has been able to roll out their FreeSync implementation of variable refresh back in March of this year, when the first DPAS-enabled monitors shipped.

Since then AMD has been relatively quiet (no doubt gearing up for their big GPU launch). However as it turns out they have been hard at work at expanding FreeSync past the realm of DisplayPort monitors, and they are for the first time showing off that technology at their suite at Computex 2015.

AMD's demonstration and the big revelation from the company is that they now have a prototype implementation of FreeSync-over-HDMI up and running. Powered by an R9 200 series card (we'd wager 290X), AMD's demonstration involved running their windmill FreeSync demo against the prototype FreeSync-enabled HDMI monitor to showcase the viability of FreeSync-over-HDMI.

We wasted no time in tracking down AMD's Robert Hallock for more details, and while AMD isn't being super deep at this time – it’s a proof-of-concept prototype after all – we do have a basic understanding of what they are up to.

The monitor in question is running a Realtek TCON, with AMD and Realtek developing the prototype together. The TCON itself is by all indications a bog-standard TCON (i.e. not custom hardware), with the only difference being that Realtek has developed a custom firmware for it to support variable refresh operation and the FreeSync-over-HDMI technology.

On the signaling side, AMD tells us that they're running a custom protocol over HDMI 1.4a. As one might expect, the necessary functionality doesn't currently exist in HDMI, so AMD went and added the necessary functionality to their driver and the Realtek firmware in order for both ends to operate. Compared to FreeSync-over-DisplayPort all other operation is the same from what we're told, so the end result is the same kind of variable refresh support currently found in DPAS-enabled monitors, except now over HDMI instead of DisplayPort.

The goal here from AMD is very similar to what they did with DisplayPort last year. The company wants to introduce variable refresh support into the HDMI standard, making it a standardized (and common) feature of HDMI. The payoff for AMD and their users would be that getting variable refresh support into HDMI would allow FreeSync to potentially work with many more monitors, as DisplayPort is not found in all monitors whereas HDMI is. This is especially the case in cheaper monitors, which of course make up the bulk of monitor sales.

Because AMD has been working with Realtek on this, it was unknown if other TCON manufacturers would have issues writing firmware. However if variable refresh were implemented into the HDMI standard, then there's no reason to believe it wouldn't eventually be a solved issue. Meanwhile the fact that Realtek is doing this via custom firmware on a standard TCON does technically open up the possibility of flashing existing monitors to enable such functionality, but given the fact that this hasn't happened for DisplayPort monitors, it's unlikely here as well.

In any case, AMD isn't saying too much else at this time. With a proof-of-concept up and running, AMD can now begin attempting to influence the necessary parties to add the feature to HDMI, and to get customers demanding the technology.

First 30Hz Minimum Refresh Rate DisplayPort Adaptive-Sync Monitor: Nixeus NX-VUE24

Along with the FreeSync-over-HDMI demo, AMD also had one bit of FreeSync news at Computex. As regular readers are likely aware, all of the current DPAS monitors have a minimum refresh rate over 30Hz – typically 40Hz or 48Hz – which unfortunately for AMD’s FreeSync efforts is counterproductive to their goals since you lose the bulk of the benefits of FreeSync when framerates fall below the minimum refresh rate. And although this is a monitor limitation rather than a DPAS/FreeSync limitation, AMD is still looking to push vendors to get lower minimum rate monitors on the market and to promote those monitors.

To that end, monitor vendor Nixeus has announced the first 30hz minimum refresh rate DPAS monitor, the NX-VUE24. The NX-VUE24 is a 24”, 1080p TN display that supports variable refresh rates from 30Hz up to 144Hz. A 1080p TN monitor is admittedly not likely to set the world on fire at this point, but it’s still an important milestone in getting 30Hz-minimum DPAS displays out in to the market. And at 1080p and just 24”, this will likely be the most affordable/cheapest variable refresh monitor yet.

Update: We also have confirmation that the NX-VUE24 supports pixel overdrive

Nixeus has not yet announced a release date or price for the monitor, but they tell us it should be coming soon.

FreeSync’s Teething Issues

Finally, while we had a chance to talk to AMD about FreeSync, we asked them about some of the barbs NVIDIA has been flinging their way lately, particularly on the subject matter of minimum refresh rates and pixel overdrive. Though NVIDIA is not above poking at AMD when it suits them, these were still important points that we wanted to hear AMD's answer to.

On the matter of pixel overdrive, AMD has clarified that pixel overdrive can work with FreeSync, but it is up to the monitor manufactures. DPAS/FreeSync doesn’t offer any control over overdrive to the video card, so whether any overdrive happens is up to the monitor manufacturer, who would need to implement it in their scaler. Ultimately pixel overdrive is not a required part of the DPAS standard, so its presence is going to be on a monitor-by-monitor basis, and the quality of any overdrive solution is up to the vendor. As with NVIDIA’s solution, this all boils down to doing frame delivery prediction and adjusting their overdrive values accordingly, with DPAS monitor manufacturers needing to do that in their scaler as part of their per-frame operations (just as how it works today on fixed refresh rate monitors.

Meanwhile on the subject of minimum refresh rates, AMD’s comments were a bit less concrete, but also a bit more optimistic. How minimum refresh periods are handled is ultimately up to FreeSync; there needs to be a refresh within the maximum pixel decay period in order to maintain the display, but it’s up to AMD how they want to do those refreshes. For 144Hz monitors this can mean just running a quick refresh over 7ms, whereas for 60Hz monitors the subject is a bit trickier since a refresh takes 16ms.

In any case the message from AMD has been that they have the ability to change their minimum refresh behavior as they see fit or as they develop better ways to handle the situation. However absent any concrete details at this time, all we can do is wait and see if and when AMD makes any changes. AMD clearly isn’t wanting to commit to anything right now, at least not until they have something ready to deploy.

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  • MobiusPizza - Wednesday, June 3, 2015 - link

    Your argument about AMD software or hardware support is totally invalid. Freesync is just a specification, there is no hardware or software by AMD. The ghosting issues is up to the monitor manufacturer to solve, they can include a hardware buffer for example, which will make Freesync on par with Gsync with regards to behavior when falling below the minimum supported refresh rate. Reply
  • Shark321 - Wednesday, June 3, 2015 - link

    This is 100% wrong. If it were no hardware or software by AMD then why only a tiny fraction of AMD video cards supports freesync? You need both AMD hardware and drivers on the GPU side in order for freesync to work. There is no working solution without AMD, even if possible in theory. Reply
  • caqde - Thursday, June 4, 2015 - link

    You are wrong. The Implementation requires hardware on both sides. The GPU and the Monitor. The monitors implementing side is based on Standards. On the GPU side the GPU manufacturer AMD/Nvidia/Intel needs to support talking to the Monitor using this standard (Adaptive Sync). This part is Software and Hardware. AMD's Implementation is Freesync. But Intel and Nvidia are FREE to implement their own solution. Nothing is stopping them from implementing this and AMD's solution is not the only answer possible. (Nvidia GSync does not implement Adaptive Sync but it could in the future) Reply
  • chizow - Thursday, June 4, 2015 - link

    @MobiusPizza: Please stop spreading misinformation and writing checks that AMD can't or isn't willing to cash, specifically the bit about the hardware buffer. Reply
  • Refuge - Wednesday, June 3, 2015 - link

    If everyone supported it (nVidia and Intel) then it would get a lot more attention from a lot more people. Its the age old Kumbaya tale.

    If these companies would work together for the betterment of all customers rather than just their own shareholders, then freesync would be agnostic from AMD or nVidia or Intel, and every monitor would have it, and it would scare from 9hz to 2000hz.

    Because to be honest, this should have been a standard long ago, I love greenteam, I appreciate their ingenuity and skill. But they are doing this wrong, they are doing well, but they are doing it wrong.
    Reply
  • chizow - Wednesday, June 3, 2015 - link

    Who was doing it right, before Nvidia invented VRR and brought it to market, and got it right the first time? Reply
  • Michael Bay - Thursday, June 4, 2015 - link

    You don`t get it: they are wrong because they are doing it well, like, totally wrong. Reply
  • Refuge - Wednesday, June 3, 2015 - link

    Also, with it being an open standard it isn't really subject to AMD's "Terrible driver track record" Reply
  • chizow - Thursday, June 4, 2015 - link

    They spec'd the standard and the implementation and it has to go through their logo program, so of course it is subject to AMD's terrible support record. In fact, it is this approach and mentality that is clearly echoed by their supporters cements this, notion, AMD loves to throw out open standards and then just expects work from ?SOMEONE? to make it good. Ridiculous lol. Reply
  • pogostick - Tuesday, June 9, 2015 - link

    Yeah. Like HBM. Ridiculous. Reply

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