Pixel-pushing power
I've already mentioned that the Radeon X1900 is a forward-looking design that's heavy on pixel shaders at the expense of other things. The numbers below will illustrate that point. These aren't measures of pixel-shading power, just basic measures of theoretical peak ability to draw pixels onscreen. These numbers become less relevant as architectures like the X1900 take hold, but they're still noteworthy indicators of performance potential, especially in older games and apps.

Core clock
(MHz)		 Pixels/
clock		 Peak fill rate
(Mpixels/s)		 Textures/
clock		 Peak fill rate
(Mtexels/s)		 Memory
clock (MHz)		 Memory bus
width (bits)		 Peak memory
bandwidth (GB/s)
Radeon X1600 XT 590 4 2360 4 2360 1380 128 22.1
GeForce 6800 325 8 2600 12 3900 700 256 22.4
GeForce 6600 GT 500 4 2000 8 4000 1000 128 16.0
Radeon X800 400 12 4800 12 4800 700 256 22.4
GeForce 6800 GS 425 8 3400 12 5100 1000 256 32.0
GeForce 6800 GT 350 16 5600 16 5600 1000 256 32.0
Radeon X800 XL 400 16 6400 16 6400 980 256 31.4
GeForce 6800 Ultra 425 16 6800 16 6800 1100 256 35.2
GeForce 7800 GT 400 16 6400 20 8000 1000 256 32.0
Radeon X1800 XL 500 16 8000 16 8000 1000 256 32.0
Radeon X850 XT 520 16 8320 16 8320 1120 256 35.8
Radeon X850 XT PE 540 16 8640 16 8640 1180 256 37.8
XFX GeForce 7800 GT 450 16 7200 20 9000 1050 256 33.6
Radeon X1800 XT 625 16 10000 16 10000 1500 256 48.0
Radeon X1900 XT 625 16 10000 16 10000 1450 256 46.4
GeForce 7800 GTX 430 16 6880 24 10320 1200 256 38.4
Radeon X1900 XTX 650 16 10400 16 10400 1550 256 49.6
GeForce 7800 GTX 512 550 16 8800 24 13200 1700 256 54.4

Despite its additional pixel shading power, the Radeon X1900 XT has no more fill rate than the Radeon X1800 XT. In fact, its memory is clocked slightly slower than the X1800 XT, believe it or not. The XTX offers a minor bump over the X1800 XT in terms of fill rates and memory clocks, but it's not enough to match the multitextured fill rate or memory bandwidth of the GeForce 7800 GTX 512.

3DMark's synthetic fill rate tests allow us to put those theoretical numbers to the test. Few cards can reach their theoretical peaks in the single-textured test, but most achieve numbers close to their peaks in the multitextured test. The Radeon X1900 XT just trails the X1800 XT here—a virtual tie—while the XTX edges out the 256MB version of the GeForce 7800 GTX.