Pixel filling power
Ah, fill rate. It is the pixel-pushing power that leads us to pursue ever higher numbers of pixel pipelines and clock speed. Fill rate can determine whether a game runs well at a given resolution with lots of antialasing and texture filtering, and so it's one of the primary determinants of overall graphics performance. It's also tied closely, in real-world scenarios, to memory bandwidth. Here's how the Radeon X800 stacks up on both fronts.

  Core clock (MHz) Pixel pipelines Peak fill rate (Mpixels/s)Texture units per pixel pipeline Peak fill rate (Mtexels/s) Memory clock (MHz) Memory bus width (bits) Peak memory bandwidth (GB/s)
GeForce 62003004120011200TBD128TBD
Radeon X30032541300113004001286.4
Radeon X600 Pro40041600116006001289.6
GeForce FX 5700 Ultra475419001190090012814.4
Radeon 9600 XT50042000120006001289.6
Radeon X600 XT500420001200074012811.8
GeForce 66003008*120012400TBD128TBD
Radeon 9800 Pro380830401304068025621.8
Radeon 9800 Pro 256MB380830401304070025622.4
GeForce FX 5900 XT400416002320070025622.4
Radeon X70040083200132006001289.6
Radeon 9800 XT412832961329673025623.4
Radeon X700 Pro420833601336086412813.8
Radeon X700 XT4758380013800105012816.8
GeForce 6800 3251239001390070025622.4
GeForce 6600 GT AGP5008*20001400090012814.4
GeForce 6600 GT5008*200014000100012816.0
Sapphire Radeon X8003921247041470470025622.4
Radeon X8004001248001480070025622.4
GeForce 6800 GT35016560015600100025632.0
Radeon X800 Pro4751257001570090025628.8
Radeon X800 XL4001664001640098025631.4
GeForce 6800 Ultra42516680016800110025635.2
Radeon X800 XT50016800018000100025632.0
Radeon X800 XT Platinum Edition52016832018320112025635.8
Radeon X850 XT52016832018320112025635.8
Radeon X850 XT Platinum Edition54016864018640118025637.8
* The GeForce 6600 GT has eight pixel pipes and four ROPs, so it can only write 4 pixels per clock when applying a single texture. The pixel pipes and ROPs are connected via a fragment crossbar, so they are very efficient.

Sapphire's X800 is priced directly between the GeForce 6600 GT and the GeForce 6800. Specs-wise, though, it looks an awful lot like a GeForce 6800, with 4 more pixel pipes and twice the memory bus width of the GeForce 6600 GT. Those attributes give the Radeon X800 more theoretical peak fill rate and memory bandwidth than the 6600 GT. Let's put that theory to the test with some synthetic fill rate benchmarks.

With multiple textures being applied per pixel, the X800 reaches very near to its theoretical peak fill rate. When doing single texturing, interestingly enough, the X800's vast theoretical advantage over the GeForce 6600 GT fails to materialize. The 6600 GT's unique fragment crossbar config, which is tied to only four raster output units, certainly doesn't seem to harm it in practice. Still, the X800's 12 pipes give it the edge overall.

That sets the expectations for the X800. Let's see if it can live up to them.