Though they don’t get quite as much ongoing attention as video cards due to their slower update cadence, one of the nicer innovations in the last few years in the gaming hardware ecosystem has been variable refresh displays. By taking displays off of a fixed refresh rate and instead coupling it to the frame rate, the state of gaming on the PC has become a lot more pleasant, especially in the irksome area between 30 and 60 frames per second.
As it was NVIDIA to make the first move here in 2013, AMD only ended up rolling out their own variable refresh solution in 2015. Under the brand name FreeSync, AMD leveraged the VESA’s optional DisplayPort Adaptive-Sync standard to offer variable refresh in conjunction with the major monitor manufacturers. The fact that AMD was second to the market didn’t dampen their enthusiasm (or customers’) too much, but it did mean that until recently they were playing catch-up with NVIDIA on extra features. AMD finally reached (practical) feature parity with NVIDIA just last month when they added support for borderless windowed mode.
But now that AMD has caught up with NVIDIA, their attention is quickly shifting to what they need to do to get ahead and where they can go next. Which is a harder area to tackle than may at first be apparent; variable refresh is a fundamental feature, and once you have support for it, it shouldn’t require constant fiddling. The end result is that for their next monitor technology initiative, AMD is tackling more than just refresh rates. Looking to address the high-end market with a new solution for both HDR and variable refresh, today AMD is taking wraps off of this initiative: FreeSync 2.
Trying to explain FreeSync 2 can get a bit tricky. Unlike the original FreeSync that it takes its name from, it’s a multi-faceted technology: it’s not just variable refresh, instead it’s HDR as well. But it’s also a business/platform play in a different way than FreeSync was. And while strictly speaking it’s a superset of FreeSync, it is not meant to replace FreeSync wholesale. Perhaps the best way to think of FreeSync 2 is that it’s a second, parallel initiative that is focused on what AMD, its monitor partners, and its game development partners can do to improve the state of high-end monitors and gaming.
In terms of features then, what is easily the cornerstone feature of Freesync 2 – and really its reason to be – is improving support for HDR gaming under Windows. As our own Brandon Chester has discussed more than once, the state of support for next-generation display technologies under Windows is mixed at best. HiDPI doesn’t work quite as well as anyone would like it to, and there isn’t a comprehensive & consistent color management solution to support monitors that offer HDR and/or color spaces wider than sRGB. The Windows 10 Anniversary Update has improved on the latter, but AMD is still not satisfied with the status quo on Windows 10 (never mind all the gamers still on Windows 7/8).
As a result FreeSync 2 is, in part, their effort to upend the whole system and do better. For all of its strengths as a platform, this is an area where the PC is dragging compared to consoles – the PlayStation 4 was able to add functional & easy to use HDR10 support to all units as a simple software update – so for AMD they see an opportunity to improve the situation, not only making HDR support more readily available, but improving the entire experience for gamers. And to do this, AMD’s plans touch everything from the game engine to the monitor, to make HDR the experience it should be for the PC.
Diving into the technical details then, AMD’s solution is essentially a classic one: throw out what isn’t working and make something that works better. And what isn’t working right now? As mentioned before, Windows doesn’t have a good internal HDR display pipeline, making it hard to use HDR with Windows. Meanwhile HDR monitors, though in their infancy, have their own drawbacks, particularly when it comes to input lag. The processors used in these monitors aren’t always capable of low-latency tone mapping to the monitor’s native color space, meaning using their HDR modes can add a whole lot of input lag. And worse, current HDR transports (e.g. HDR10) require tone mapping twice – once from the application to the transport, and second from the transport to the native color space – so even if a monitor has a fast processor, there’s still an extra (and AMD argues unnecessary) step in there adding input lag.
FreeSync 2 then attempts to solve this problem by upending the whole display pipeline, to get Windows out of the way and to offload as much work from the monitor as possible. FreeSync 2 in this respect, is essentially an AMD-optimized display pipeline for HDR & wide color gamuts, in order to make HDR easier to use and better performing as well.
The FreeSync 2 display pipeline as a result is much shorter (i.e. lower latency), and much more in AMD’s control. Rather than the current two-step process, AMD proposes to have a single step process: games tone map directly to the native color space of a FreeSync 2 compliant monitor, AMD’s drivers and hardware pass that along, and then the monitor directly accepts the display stream without further intensive processing. The end result is that latency is potentially significantly reduced by removing the second tone mapping step from the process.
Meanwhile on the usability side, AMD’s drivers and FreeSync 2 monitors would implement a form of automatic mode switching.
