FSAA & Image Quality Comparison - 3dfx vs ATI vs NVIDIAby Anand Lal Shimpi on July 27, 2000 3:11 AM EST
- Posted in
Hardware vs. Software
One of the most confusing things about the various methods of implementing FSAA in a video card is the debate over whether the feature is implemented in "hardware" as a feature of the chip or in "software," meaning that it is a function of the drivers alone and can be enabled on any card that the drivers support.
The main thing to understand here is that regardless of whether FSAA is supported in "hardware" through 3dfx's T-Buffer or in "software" through the NVIDIA Detonator drivers, it currently takes the same performance hit. If you're implementing a 2 sample FSAA algorithm, you're going to have effectively 1/2 the fill rate at your disposal since you're rendering twice as many pixels. This applies to all of the cards we're talking about today, the Voodoo4/5, the Radeon and the GeForce/GeForce2 MX/GeForce2 GTS.
The second thing to keep in mind is a very simple principle, but it is commonly misunderstood when talking about FSAA performance. As we just finished pointing out, regardless of whether you're talking about a Voodoo5, a Radeon or a GeForce2 GTS, if you make any one of those cards render twice as many pixels, it's going to effectively have 1/2 the fill rate.
3dfx's 2 sample FSAA offers the same theoretical performance hit as NVIDIA's 2 sample FSAA since in both cases we're decreasing the available fill rate by 50% by rendering twice as many pixels. While it is true that the Voodoo5 and the GeForce2 GTS perform differently when their respective 2 sample FSAA modes are enabled, that is not because one card is "faster" at FSAA than another, it's simply because the two cards do perform differently.
Now that we've gotten that out of the way, let's move onto the various forms of FSAA offered by the three manufacturers.