FreeSync overview
AMD's FreeSync is a display technology which allows a graphics processor to synchronise its frame-rate with a compatible display using a Dynamic Refresh Rate (DRR). The technology is built on top of the DisplayPort Adaptive-Sync standard that is part of the DisplayPort 1.2a specification.
Adaptive-Sync and FreeSync are not identical since Adaptive-Sync requires an ecosystem of hardware; a compatible GPU and display with the right scaler, and software in order to deliver a functional DRR solution. FreeSync effectively denotes the complete package for implementing the Adaptive-Sync technology into the end-user experience.
The notable and pre-existing rival to AMD's FreeSync is Nvidia's G-Sync and as the naming of AMD's new technology would suggest, the point of divergence is a slightly lower implementation cost. This stems from AMD's decision to not apply licensing fees since the underpinning technology is from the open DisplayPort specification. A scaler module is still required but the main difference is that this module isn't proprietary, like with G-Sync.
AMD has worked with three leading scaler manufacturers - Realtek, Novatek and MStar - to incorporate FreeSync technology into their latest generation of scalers that are found in the various screens. The only additional cost borne by the scaler manufacturer/monitor vendor rests with ensuring the FreeSync-supporting firmware is in place. AMD's technology doesn't have a literal licensing cost to it, but there is a small cost overhead incurred when compared to standard displays. How this plays out for retail monitors will only be known once we can compare like-for-like models.
Back on point, AMD's FreeSync also has the theoretical potential for a refresh rate range of 9-240Hz, compared to G-Sync's 30-144Hz. The widest range on offer for a shipping FreeSync monitor is 40-144Hz which means Nvidia solutions, such as the ROG Swift PG278Q, actually come out in pole position. In that regard Nvidia has a distinct advantage since it has more carefully mandated the minimum end-user experience. AMD claims it still has to approve each FreeSync monitor, but the minimum refresh rate range is clearly a lot lower given LG's FreeSync monitors support 48-75Hz only.
FreeSync and G-Sync are both dynamic refresh-rate technologies that function when the frame-rate is within the supported range of the monitor. In practice, this doesn't always happen, since the frame-rate can be too low or high for the display to synchronise with.
In terms of dealing with the out-of-range framerates Nvidia G-Sync requires that V-Sync be enabled for G-Sync to work. AMD, on the other hand, gives the end user the choice between having V-Sync on or off when using FreeSync. While neither solution is glamorous it's nice to have the choice between the rock, tearing, and the hard place, stuttering.
AMD FreeSync technology is limited to the company's newest graphics processing units. For desktop users this means a choice of Bonaire-, Tonga- or Hawaii-based GPUs while APUs users can get FreeSync with any Kaveri-based APU. No information about mobile FreeSync support has been disclosed by AMD at this time. For reference, Nvidia's G-Sync is supported on the bulk of GTX 600, 700, 900 and Titan series desktop GPUs.
What's more, AMD is not supporting CrossFire FreeSync from the get-go, unlike rival Nvidia, and we'll likely wait until mid-April until a compatible driver is released.
