It's potentially a revolution in the console space - just as it has been for PC gamers. Variable refresh technology is a big win for improving the game experience, lessening judder and removing screen-tearing. It's a pretty simple concept really, levelling out performance by putting the GPU in charge of when the display should present a new frame. It's a game-changer. No longer are unlocked frame-rates a problem - in fact, 40-50fps gameplay can look almost as smooth as 60fps. It's a remarkable trick, but crucially, it works. Nvidia's G-Sync led the way, but it's AMD's alternative - FreeSync - that has been built into Xbox One, and we've finally had the chance to test the technology. Clearly it's still early days, but at its best, the results are quite remarkable.
Let's begin by laying out the basics. Microsoft's variable refresh implementation only works with FreeSync screens - G-Sync monitors are incompatible - but the Xbox version of the tech is bespoke, with some pretty big differences compared to AMD's rendition. There's strong compatibility though: you'll need a display that supports FreeSync over HDMI (as opposed to the more common DisplayPort) but on the Microsoft end at least, there's support for 720p, 1080p, 1440p and 4K outputs. We've had confirmation that both Xbox One S and Xbox One X are invited to the party, but the firm also told us that older launch model hardware also gets the upgrade.
Choosing a FreeSync display isn't as easy as you might think. Our testing was conducted using an Asus VP28U - a native 4K screen that support FreeSync over HDMI, but we found that it only supported variable refresh at 1080p resolution, meaning we needed to set our Xbox One X accordingly. So in searching out a 4K screen for an X owner, FreeSync over HDMI 2.0 is a must. Secondly, there's the concept of the FreeSync 'window', or the 'range' as it's described on the AMD list of supported displays. This is the range of frequencies in which FreeSync is actually active. On the VP28U, this is defined as 40-60Hz (very common for 4K screens) but the wider it is, the better the FreeSync experience. The problem here is that the wider ranges only tend to be associated with lower resolution, non-4K screens - potentially making the FreeSync tech a better match for the 1080p-orientated Xbox One S.