Performance wise, NVIDIA's GeForce2 GTS does have the Voodoo5 5500 beat. There's no way you can argue that statement, but once you factor in FSAA performance and image quality the GeForce2 GTS all of the sudden loses its appeal. When the GeForce2 GTS was released its 5.16 drivers wouldn't even support FSAA in Direct3D. Later on with the release of the Detonator 5.22 drivers the GeForce2 GTS gained FSAA support but the performance was far from satisfactory, by this point we just assumed that if you really wanted FSAA support the Voodoo5 would be your best choice.

As we mentioned in our Detonator 5.22 investigation, the performance of NVIDIA's D3D FSAA implementation could most definitely improved with some better drivers. With the release of the leaked Detonator 5.30 drivers we figured that it was about time to revisit NVIDIA's Direct3D FSAA performance but in doing that we discovered something else that applied to their FSAA under OpenGL games.

First let's take a quick look at how NVIDIA's FSAA works in general as well as under OpenGL:

Taken from our NVIDIA GeForce2 GTS Review.

NVIDIA’s FSAA works by using a method called Supersampling.  The way supersampling works is that the scene is actually rendered at a higher resolution and then scaled down to the desired resolution before being displayed.  As you already know, the higher the resolution you run at, the fewer aliasing effects are present since you have more pixels on the screen to naturally remove those effects. 

Under OpenGL applications, NVIDIA’s FSAA can work in one of three modes (much like how 3dfx’s FSAA can be run in either 2-sample or 4-sample mode).  The three FSAA settings are as follows:

·        1.5 screen resolution (lowest quality)

·        2x screen resolution, with LOD’s (MIPMaps) at the native game resolution

·        2x screen resolution with MIPMaps at the 2x resolution. (highest quality)

So if you’re running a game at 640 x 480, the first FSAA option will render the scene at 960 x 720 (640 * 1.5 x 480 * 1.5) and then scale it back down to 640 x 480 for displaying. 

Depending on who you ask (3dfx or NVIDIA) you will get varying responses as to exactly what each of these modes looks like.  3dfx will have you believe that their 4 sample FSAA looks better than all of these modes while NVIDIA will have you believe that their third FSAA setting looks the best. 

The final decision is up to you, but unfortunately, the 5.16 drivers we used for our GeForce 2 GTS tests would only allow us to enable the first setting, which renders each scene at 1.5x the screen resolution so we could only provide you with screen shots at this setting and not the other two settings.

The last paragraph has held true with every driver release until now. The Detonator 5.22 drivers, while adding support for FSAA under Direct3D failed to include the support for the other two modes of FSAA under OpenGL. The Detonator 5.30 drivers managed to fix this feature and now GeForce2 GTS owners have the ability to adjust their FSAA quality under OpenGL as well as under Direct3D. So how do you manipulate the FSAA level for OpenGL?

FSAA in OpenGL
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