Emultra, the overpriced GF3 performing Parhelia does have a fantastic ability with its Fragment AA. However it can't always be applied (games or combinations may not permit), misses some jaggies and results in eratic frame rates. It does however take a VERY small perf hit (about the same as GF3 & GF4 with 2xAA) and does give generally excellent results. However since the FPS are 'only' that of a GF3 or Rad8500 taking a small hit actually means it is still far slower than GF4 cards. A final note is that if FxAA can't be used the Parhelia's only other option is to use a VERY slow MASSIVE HIT 4xAA. I think 99% of folk will agree that Parhelia is not worth the price tag!
Anyway, here's some info regarding AA.
:lol: The original AA technique used by both nVidia & ATI was Super-Sampling AA. This worked by rendering more pixels than were req for the final image on screen. So for a 800x600 image, 2xAA(SS) renders 1600x600 and 4xAA(SS) renders 1600x1200, therefore there is 2 horizontal pixels for every final 1 in 2xAA (4 for every final pixel in 4xAA) and this is where the extra info is found to base the final colour of the final pixel which then 'leaves' the card. That way there isn't quite the hit of actually running in a higher res but you gain much of the quality that would come from a higher res. Especially useful for people whose monitor can't handle the higher res.
The newer technique (well it's more of an enhanced 3dfx technique) only currently used by nVidia GF3 & GF4 (perhaps the Xabre too but under the title 'Jitter Free AA') is Mutli-Sampling AA. This uses mathematics and complex algorithms to guess the correct AA for each pixel and largely blur the image (which is 75% of what AA does anyway) and that's why details and textures aren't as sharp with AA but are less jagged. AA-MS is much faster than AA-SS but does result in blurrier images, although this can be overcome with Aniso or 4xS AA. The GF4 does use an enhanced version of AA-MS IIRC by taking the samples at slightly different locations which is intended to give better results. Also 4xS-AA is an option which uses some SS-AA techniques mixed with MS-AA which negates the need for Aniso and keeps textures and detail sharp. 4xS is for DirX only but since OpenGL has Aniso it does't really matter. AA-Quincunx from GF3 & GF4 takes a 2xAA hit but achieves 4xAA results, just more blurry (so is great with Aniso). It's to do with rendering 2xAA but shifting the pixels up a bit in order to give 4 pixel calculations. QxAA with Aniso is faster and better looking than 4xAA and is the best solution IMHO.
The Matrox Parhelia-512 uses Fragment Super-Sampling which works out the key jagged lines and only performs AA-SS on these parts of the image. This keeps the quality of AA-SS but removes most of the hits of unneccessarily blurring every single pixel. The downside is that some frames will req much more AA than others meaning the frame rate will be much more erratic, some jaggies are missed and it can't always be used. You will most likely need an average frame rate of around 100 FPS with just to ensure the rate doesn't dip below 30 FPS. If FxAA can't be used then the P512 has to resort to 4xAA (SS) which takes a big perf hit.
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