S.T.A.L.K.E.R.: Shadow of ChernobylS.T.A.L.K.E.R.: Shadow of Chernobyl, previously known as S.T.A.L.K.E.R.: Oblivion Lost, is a first-person shooter computer game by Ukrainian developer GSC Game World, published in 2007. It features an alternate reality theme, where a second nuclear disaster occurs at the Chernobyl Nuclear Power Plant in the near future and causes strange changes in the area around it. The game has a non-linear storyline and features gameplay elements such as trading and two-way communication with NPCs. The game includes elements of role-playing and business simulation games.
In S.T.A.L.K.E.R., the player assumes the identity of an amnesiac "Stalker", an illegal explorer/artifact scavenger in "The Zone", named 'The Marked One'. "The Zone" is the location of an alternate reality version of the Chernobyl Power Plant after its second (fictitious) explosion, which contaminated the surrounding area with radiation and caused strange otherworldly changes in local fauna, flora and even the laws of physics. "Stalker" in its original (film) context roughly meant "explorer" or "guide", as the stalker's goal was to bring (guide) people into the Zone. On July 11th, 2007, GSC Game World announced a prequel S.T.A.L.K.E.R.: Clear Sky which would be released on 5th of September in 2008
STALKER is a special case when it comes down to Anti Aliasing… as you’ll see
STALKER's game engine uses a form of rendering called Deferred Shading. This effectively means it cannot support proper Antialiasing which would remove all the jagged outlines in the game world, regardless of which type of graphics card you have. Thus the Antialiasing slider has no real impact on performance or image quality. Do note however that with the most recent Nvidia Forceware drivers that you can 2xAA Antialiasing in STALKER through the graphics card control panel. This will reduce jaggedness, primarily on terrain and buildings rather than the foliage; however it can come at a very high cost in performance. (src: Tweakguides.com
Looking at the performance numbers under Vista do reveal that there is no performance difference between the different ES (Edge Smoothing) settings. With the GTX 280 we can enable 2xAA and performance drops sharply, the game is still playable with an avg FPS of 45 but there’s not much headroom.
The performance difference between XP and Vista for the GTX 280 is negligible (+2.5%); the HD 4870 X2 under XP is quite another story, without ES enabled performance is all ok at ~93fps, as soon as the ES slider is moved it seems CrossFire is no longer working as performance drops sharply. Most likely a driver issue.
For a detail view of the results, with AA scaling and XP -> Vista Scaling see
this table
...8xAA on ATI should be compared to 8xQAA on nV, not the 8xAA which is 4xMSAA based CSAA mode
...16xAA on ATI effectively turn the card into single chip card which can do 16xMSAA, since both chips render the same frame with different AA patterns
...16xAA on nV is 4xMSAA based CSAA mode and 16xQAA on nV is 8xMSAA based CSAA mode
So 16x and 8x comparisons in your graphs are far from being 'fair' or 'apples-to-apples', the 8xAA should have ATI 8xAA vs nV 8xQAA (8xQAA = 8xMSAA) and 16xAA shouldn't even exist since the GTX280 can't do 16xMSAA which is (practicly) what the HD4870X2 is doing by blending the same frame rendered twice with different AA patterns.