Before we start on our first pass at testing we should take note of two core inadequacies with current FreeSync as it is supported by the Catalyst 15.3.1beta drivers.
The first, and most glaring as things stand, is a lack of FreeSync support whilst in multi-GPU Crossfire configurations. This only applies to a tiny fraction of AMD customers but it's still a flagship configuration, and would presumably also impact users of their current flagship GPU the Radeon R9 295X2. We understand that AMD are planning a release of a driver which supports Crossfire FreeSync as soon as possible with April penciled in, and for many of their core customers that cannot come soon enough.
A second issue, and similarly fringe case, is that FreeSync isn't currently supported in dual-Display mode. Exclusive Fullscreen mode is mandatory for FreeSync and effectively negates secondary monitor use, a factor which is important for many streamers. It's currently not yet known if multi-monitor/Eyefinity support is planned for FreeSync, but it is perhaps the largest oversight we envision that would affect enthusiast gamers.
With that aside, on to the testing:
The performance impact of FreeSync appears to be effectively nil, which is a great benefit for gaming when you’re trying to eek out every frame you can from potentially stretched hardware.
Without doubt FreeSync allows some of the smoothest gameplay possible on current hardware. Being able to vary outside of 60fps V-SYNC for sharp images and non-stuttering scenes has huge impact on immersion, precision and just overall fun. Setting the games up to do this was very straight-forward, but a reasonably brief official how-to guide would be useful for newcomers to tinkers with in-game graphics settings.
The difference was particularly noteworthy in Tomb Raider 2013, which features both darker environments and some particularly picturesq vistas. Enabling V-SYNC limited the frame rate to 144Hz (only really applicable when testing at very low image quality settings), and whilst in the 45-144Hz optimum envelope FreeSync was able to perform it magic.
Thief by contrast, being a stealth game and particularly dark in general, saw less of a benefit except overall. However specific scenes that feature bright object on dark backgrounds, such as windows or ghosts, didn’t exhibit tearing and was significantly sharper in appearance.
A very specific oddity occurred during out testing of BioShock Infinite. Contrary to experience with Tomb Raider and Thief the game exhibited tearing at >60fps, but none whilst operating in the 40-60fps range. It’s possible that the game wasn’t registering our monitor as a 144Hz model, causing some conflict with Freesync. This was reinforced when V-SYNC was enabled, limiting the frame-rate to a maximum of 60 (rather than the expected 144) but showing perfect synchronisation when dropping as low as 40Hz (i.e. within the Acer XG270HU’s FreeSync envelope).
The solution was simple however. Bioshock Infinite, unlike Tomb Raider and Thief, inherits it monitor refresh rate settings from the OS rather than have an in-game setting. Leaving it at the default of 60 mimicked the dynamics of a 40-60Hz FreeSync monitor rather than the correct 40-144Hz behaviour. Correcting this oversight immediately solved the problem, and is something news users should be aware of when using FreeSync and other high refresh rate displays.