The test results were pretty interesting. Unfortunately I wasnâ€™t able to run Half-Life 2 on the X1800 XT, since Valve decided to update the code and break all of the demos that everyone uses for benchmarking. However Far Cry threw up some interesting numbers. As expected the X1800 XT was CPU locked at the lower resolutions, much like the 7800 GTX. However, the 7800 GTX was CPU locked at about 20fps above the X1800 XT. The 7800 GTX remained in the lead up to the point where the CPU ceased to be the limiting factor â€“ then the X1800 XT edged ahead. I quizzed ATI about this and was told that the X1800 XT does have a more significant CPU overhead than the 7800 GTX, but it scales better once the CPU is out of the equation.
Looking at both 3DMark 03 and 05, the X1800 XT edged ahead of the 7800 GTX, except in 03, when there was no FSAA or AF enabled. Doom 3 didnâ€™t throw up any surprises, with the 7800 GTX well ahead of the X1800 XT, but then nVidia cards have always performed better under OpenGL.
Unlike the X1800 XT, the XL is a single slot solution, but it retains the twin dual-link DVI ports. Itâ€™s only available in a 256MB configuration, and as mentioned already, the memory runs a full 500MHz slower than the XT! Theoretically you could put an X1800 XL in a small form factor system, although the card is very long and gets extremely hot during heavy use.
Since I was able to take a Radeon X1800 XL back with me, I was able to run a more extensive set of tests, pushing the resolution a bit harder than I was able to on the XT. I compared the X1800 XL directly with a GeForce 7800 GT, since both cards are one step down from the top end.
The 3DMark scores are almost a carbon copy of the XT vs. GTX results â€“ the X1800 XL edges ahead in all the tests bar 3DMark 03 with no image quality settings. I say almost because once I cranked the resolution up to 2,048 x 1,536 the 7800 GT took the lead in all the 3DMark 05 tests.
Further investigation showed that although the X1800 XL appeared to scale better once the CPU limitation was taken out of the equation, once the resolution was pushed up to 2,048 x 1,536, the 7800 GT gained back the ground and often took over.