Performance with FSAA
Blizzard Entertainment did not implement FSAA support in its latest StarCraft II: Wings of Liberty video game due to limitations imposed by DirectX 9 API. Nonetheless, both ATI and Nvidia quickly introduced a way to force multi-sample anti-aliasing from the drivers. Nvidia managed to enable FSAA in StarCraft II on the day of the release. While performance hit was massive, it did not make any statements, but just advised that their customers should enable it from the control panel. AMD's graphics business unit forced MSAA in the new title days after the release, with massive speed drop too, but first it issued a statement claiming that performance hit associated with enabling antialiasing was too high.
The screenshots speak for themselves. Full-scene anti-aliasing does make a difference in the game, where buildings, units and environment details are close to each other and can be zoomed in. It is hardly a life changing experience, but an option one would generally like to have.
There are also a lot of first-person shooter-like encounters in campaign mode, so smoother character edges is a nice addition. The only drawback is that in some areas, such as computer console displays, FSAA tends to blur the image, which might be one of the reasons why Blizzard decided not to override DX9 specs and enable MSAA.
Having found out that antialiasing can be enabled and that it does improve the quality of the game, we decided to test our graphics cards with the unsupported feature activated.
Considering the level of performance showed in "pure mode" it comes to no surprise that almost all of the premium competitors can pass this test at over 30 fps rate. Still, we must admit that forcing multi-sampling anti-aliasing in StarCraft II is a stress even for such a monster as ATI Radeon HD 5970. The performance is almost 50% down compared to the previous run for most of the rivals. If you are a lucky owner of a 2560x1600-capable display, you may want to consider dropping native resolution for this game.
Stepping down a notch to the performance class graphics boards we may observe that the only solutions capable of running FSAA-enabled mode at acceptable pace are ATI Radeon HD 5850 and Nvidia GeForce GTX 460 1GB. With 2560x1600 being too slow, the highest resolution that can be used on decently priced graphics boards is 1920x1080. Both of the above mentioned contenders will provide you with 40 fps average.
The Radeon HD 5830 may also be an option, since it can reach 30 fps mark, but this will not provide you with much of a performance reserve and, moreover, the GeForce GTX 460 1GB is only $30 or so more expensive. Unfortunately, owners of Nvidia GeForce GTX 275 will have to settle for 1600x900 resolution or even consider dropping FSAA at all.
Mainstream segment of the market does not leave much room for a choice. ATI Radeon HD 5770 and Radeon HD 5750 can barely cope with the increased workload and less expensive solutions just do not have enough horsepower to really use FSAA in StarCraft II.
Since StarCraft II: Wings of Liberty game engine does not support FSAA, the conclusions for our forced "eye candy" mode should be separate. The initial worries displayed by AMD's ATI unit have been justified.
The driver-forced FSAA mode is putting a huge extra stress on the graphics card. If you really want to see your system scream, build up an army and then cloak it with a Protoss Mothership. Another matter is that if you are planning on spending a lot of time in the campaign mode, you are going to see a number of game engine-rendered cut scenes (with additional effects like depth of field). And since that experience is closer to FPS rather than RTS type of games, you will be asking not for 30 but for 60 fps in order to enjoy smooth story telling.
Hopefully, FSAA in StarCraft II: Wings of Liberty is still a work in progress. Future driver updates may ensure a performance increase, or maybe Blizzard and the two IHVs will find a way to enable more efficient MSAA. But until then use forced FSAA mode with caution.