Matrox's Parhelia - A Performance Paradox

Anisotropic Filtering

One of Matrox's claims has been that with features such as anisotropic filtering enabled, the Parhelia can begin to distance itself from the competition. Remember that despite the poor performance showing of the part thus far, it still has the most memory bandwidth and vertex throughput of any GPU compared here today. With that said, enabling anisotropic filtering should not result in a significant performance hit giving the Parhelia a bit of a chance.

Before we get to the actual image quality and performance comparisons you have to realize that there are two ways that anisotropic filtering is being performed here. When anisotropic filtering is enabled, both Matrox and NVIDIA are always applying the filtering technique. The Radeon 8500 however calculates when it believes that anisotropic filtering is necessary and only uses it then, otherwise it defaults to a lesser filtering technique. The benefit of this is that the performance hit incurred while enabling anisotropic filtering is next to nothing so you can increase the degree of texture anisotropy without taking too big of a performance hit.

Matrox's control panel only allows you to enable one mode of anisotropic filtering, the equivalent of NVIDIA's 16-tap aniso. This provides us with a perfect comparison since, in theory, the Parhelia should take less of a performance hit when enabling anisotropic filtering than the GeForce4. For the Radeon 8500 we simply chose the highest degree of anisotropy which ATI lists as 16X.

Anisotropic Filtering Disabled

ATI Radeon 8500 @ 16X

Matrox Parhelia @ 16-tap

NVIDIA GeForce4 @ 16-tap

As you can see by the image comparisons, the Parhelia and GeForce4 are fairly close. It is the Radeon 8500 that is able to offer better clarity than both offerings at a much lower performance hit as you're about to see.