Image Quality Performance
GeForce 6600 GT
2XAA and 2XQAA (2X Quincunx: basic 2X multi-sample AA where neighbouring pixels are sampled in the DAC after a frontbuffer swap and blended, giving the appearance of 4XS AA at the expense of overall image fidelity) are effectively free in our DX8 IQ test, on 6600 GT. 4X and 8XS drop off due to memory bandwidth limitations. All the anisotropic filtering modes are effectively free, a result of NV4x's angle-dependant selection.
GeForce 6800 GT
With the 6800 GT all the multi-sample AA modes are effectively free, with only the mixed super-sampling mode experiencing a drop in performance. 2X AF is truly free on NV40 with the other angle dependant modes offering similar strong, but slightly less compared to 2X, performance.
GeForce 6800 Ultra
Only the mixed super-sampling AA mode isn't free on 6800 Ultra.
GeForce FX 5900 PCX
The older NV35's performance isn't that bad, by virtue of its 256-bit memory bus. None of the AF modes are free but the GPU does a good job of minimising the performance hit by using the wide memory bus. Mixed mode AA is a performance hit as expected, but the other AA modes aren't that much a burden compared to the baseline. Not NV4x-class in terms of performance but none too bad either.
