Pixel filling power
The basic math involved in graphics performance gets more complex with each new chip generation, but it remains relatively simple for the Radeon X700 XT. Because it has eight pipes running at 475MHz, the X700 XT has sweet, sweet pixel-pushing power in abundance—even more than last year's top model. Check it out.

The X700 XT's multitextured fill rate is about double that of the card it most directly replaces, the Radeon X600 XT, and it's also well above the Radeon 9800 XT's. Compared to the GeForce 6600 GT, the X700 XT is just a tad slower in multitextured fill rate but has a slight edge in memory bandwidth.

Notice the asterisk next to the number of pixel pipes on the GeForce 6600 GT. The NV43 GPU has an unconventional architecture; it essentially decouples earlier stages of the pixel pipeline from later stages, and the chip incorporates a crossbar (or switch) to feed pixel fragments from the eight pixel shader units into four raster operators (ROPs). By keeping these four ROPs fed opportunistically out of its eight pixel shader units, the NV43 makes very efficient use of its resources. This arrangement limits the GeForce 6600 GT's single-textured fill rate to two gigapixels per second, but it hardly affects real-world performance at all, as our benchmarks will show.

ATI says the X700 XT has eight "full" pixel pipes and no fragment crossbar. The X700 can output eight pixels per clock, and each pipeline can execute a single Z/stencil operation per clock, or two Z/stencil ops per clock when multisampled antialiasing is enabled.

Ok, propeller head, but how does it perform? Let's look at some synthetic fill rate tests.

The X700 XT just barely edges out the GeForce 6600 GT in 3DMark's single-textured fill rate test, despite a massive chasm between the two chips' theoretical capabilities here. This result demonstrates the elegance of the NV43's crossbar approach. The multitextured fill rate test comes out just about like one would expect, with the X700 XT just trailing the GeForce 6600 GT.

RightMark shows us a bit different result. The two cards are essentially tied in single texturing, and the 6600 GT is faster with two textures. After that, though, the X700 XT achieves higher throughput when three or more textures are applied. I should mention that the Catalyst 4.10 beta drivers we were using didn't seem to get along well with RightMark. The test stuttered a bit while running. Scores are down slightly for the 9800 XT and X600 XT compared to our previous review, and I expect the X700 XT suffered some as a result, too.

To summarize, the Radeon X700 XT can keep pace with the GeForce 6600 GT in terms of raw pixel-pushing power in the majority of our tests, and when it lags, it only lags by a small amount.