NVIDIA GeForce FX 5800 Ultra: It's Here, but is it Good?by Anand Lal Shimpi on January 27, 2003 3:50 AM EST
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With the image quality investigation over with, now it's time to look at the performance of all of these AA settings. As usual, the newcomer goes first - let's see how the GeForce FX's performance is impacted by its plethora of AA settings:
Just as NVIDIA has promised, both 2X and Quincunx modes are virtually "free" but as we all know, just because something is "free" doesn't mean it's good. Flip back a page to our comparison screenshots and you'll see that neither of these modes does much in the way of actually anti-aliasing, so we turn to some of the higher sampling methods.
Next up we have NVIDIA's 4X mode, which delivers around 3/4 the performance of the FX 5800 Ultra without any sort of AA enabled. As you can see, once you get beyond 4-samples you're reducing the performance of the card to less than 40% of its original capabilities.
Once again we look at the lower clocked GeForce FX 5800 to see how having less memory bandwidth and a lower fill rate influences performance:
The performance drops are much more pronounced on the regular 5800 as you can expect given the 20% reduction in core and memory clocks.
With the Radeon 9700 Pro we see that both the 2X and 4X modes take a slightly larger performance hit than the comparable settings on the GeForce FX, but what's truly interesting is ATI's 6X mode. A feature that ATI hasn't done a great job of publicizing is their frame buffer compression algorithm that is enabled only in AA modes, but it does boast a higher compression ratio than NVIDIA's 4:1 color compression algorithm. The benefit of this higher ratio compression algorithm can be seen in the relative performance of ATI's 6X AA setting, it delivers 60% of the 9700 Pro's original performance compared to the GeForce FX's 6XS mode with its 39%.
If you want numbers to quantify this difference, with 4X AA enabled the GeForce FX 5800 Ultra is around 9% faster at 1024x768 than the Radeon 9700 Pro (156.9 vs. 143.8), but switching on 6X AA puts the 9700 on top of the FX by no less than 53% (123 vs 80).