Image Quality Comparison in Extreme FSAA Modes

We carried out a brief check of the image quality provided by SLI and CrossFire technologies in various full-screen antialiasing modes, including extreme/hybrid ones. We took screenshots in Far Cry , Half-Life 2 , and Half-Life 2: Lost Coast at 1280x1024 resolution with 16x anisotropic filtering turned on. We also analyzed the resulting screenshots with the Compressonator utility that reveals discrepancies that hide from the naked eye.

We think 4x FSAA gives a somewhat better-looking picture on ATI’s graphics cards. If you examine the Far Cry screenshots closely, you’ll note small jaggies on the bars of the grid as rendered by the NVIDIA GeForce 7800 GTX, while there is no such jaggedness on the screenshots we made on the RADEON X1800 XT. In Half-Life 2 , however, the wire fence looks considerably better on the GeForce 7800 GTX – it disappears partially on the RADEON X1800 XT. The image quality in Half-Life 2: The Lost Coast is the same as in Far Cry , but the difference is so small as to evade the naked eye, especially during actual play.

8x FSAA and 8x SLI FSAA look almost identically on the RADEON X1800 and GeForce 7800 GTX since they are virtually identical from the technical point of view and are 4x FSAA with two times the number of samples. The antialiasing quality is nearly ideal in all cases, but the ATI RADEON again fails to render the fence wire from Half-Life 2 in full, so we should consider NVIDIA the winner of this test.

The 16x SLI AA mode available on the SLI platform is a combination of two 8xS FSAA modes which were originally hybrid modes by themselves, combining super-sampling and multi-sampling. This mode ensures the best antialiasing quality on small details and the notorious fence wire from Half-Life 2 – the stumbling block of lower-level FSAA modes – is close to ideal here. ATI’s Super AA 14x mode is a hybrid one, too, and combines 6x multi-sampling with additional 2x rotated-grid antialiasing. It handles micro-geometry very well, ensuring a somewhat better image quality than NVIDIA’s SLI AA 16x, but the above-mentioned fence still doesn’t look quite well in this case.

So it is difficult to say what hardware you get the best image quality with in games. ATI’s CrossFire working in Super AA 14x mode is the best at rendering small details, but if there are such objects in the scene as foliage, a wire fence or something, NVIDIA’s SLI platform with its SLI AA 16x mode is unrivalled. As you understand, all these FSAA modes are only really helpful if you can turn them on in real-life games and have a high enough frame rate at that. We are going to show you in the next section of the review if these extreme antialiasing modes are of any use today.