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Optimizing FSAA with your GeForce2GTS
I would like to thank Francois Garet, Hardware Project Manager at Guillemot for taking the time to explain the functioning of NVIDIA's FSAA to me. Without his patience this section would never have been possible.
We all know that apples and oranges, while both fruits, are quite different. FSAA, as developed by NVIDIA and 3dfx, are more like apples and potatoes, both are round and edible but that is about where the similarities end. The differences in these two FSAA implementations goes far beyond different FSAA codecs and goes all the way back to the original design decisions when the concepts for these boards were developed.
NVIDIA designed a one chip solution that committed them to continual chip design optimization to improve their product. 3dfx went the direction of scalable architecture based on their successful experiences with SLI. The 3dfx solution would add equal amounts of memory for each parallel processor. The NVIDIA solution would have memory added based on price points and product performance targets.
Until I can get my hands on a V4 I will not be able to prove my theories about FSAA using the 3dfx solution. I believe that 3dfx had to design a FSAA solution with very different goals than NVIDIA's. The 3dfx design allows each processor access to its memory so in effect the V5 is a pair of 32mb (V4) boards. Nothing wrong with this approach by the way. Their FSAA solution had to run in 32mb because even the V5 6000 will only have 32mb per processor.
This leads me to NVIDIA's FSAA solution. Their design needed to be scalable to many different memory configurations. Their design would accept and use from 16mb to 128mb of RAM. They designed an FSAA, to be incorporated in their drivers, which would have additional benefits as RAM was increased.
There are nine levels of FSAA, accessible from NVIDIA's Advanced Direct3D properties:
- off
- 2x mode (back buffer is 2x screen resolution; 2x1 supersampling)
- 4x mode (back buffer is 4x screen resolution with MIPMaps at the native game resolution.)
- 4x mode (back buffer is 4x screen resolution with MIPMaps at the backbuffer (higher) resolution)
- 4x mode with Gaussian blur
- 9x mode (back buffer is 9x screen resolution with MIPMaps at the native game resolution)
- 9x mode (back buffer is 9x screen resolution with MIPMaps at the backbuffer (higher) resolution)
- 16x mode (back buffer is 16x screen resolution with MIPMaps at the native game resolution)
- 16x mode (back buffer is 16x screen resolution with MIPMaps at the backbuffer (higher) resolution)