http://www.hardwaresecrets.com/article/228
In our benchmark Radeon X1800 XT with 512 MB was faster than GeForce 7800 GTX with 256 MB. Period.
Once again, we could say that Radeon X1800 XT is really faster than GeForce 7800 GTX.
As a side note, GeForce 7800 GTX model from XFX we included in our comparisons is factory-overclocked, running at 450 MHz (instead of 430 MHz) and memory running at 1.25 GHz (instead of 1.2 GHz).
See the stock X1800XT beats an overclocked 7800GTX.
http://www.tomshardware.com/2005/10/06/ati_enters_the_x1000_promised_land/
Benchmark Conclusions:
From these two synthetic and four "real world" game engines you can see that ATI has taken the 16 pixel shader and 8 vertex shader pipelines from the X850 generation and massively overhauled them into a highly efficient system. In many of the tests at 10x7 and 16x12 resolutions, the 24 and eight pipelines of the NVIDIA GeForce 7800 GTX could not keep up with the ATI X1800XT.
One of the most drastic leaps was in 3DMark 2005 where the 16x12 4xAA 8xAF score lead the NVIDIA 7800 GTX by over 1,100 marks.
Then with the OGL fix for games like Doom3 Quake 4, the X1800XT pulled ahead even more.
http://www.anandtech.com/video/showdoc.aspx?i=2556
The X1800 XT will be good competition for the 7800 GTX, besting it in many cases
The additional tests that we've run help to solidify our assessment of ATI's situation with the X1000 line. Our tests show that the high end ATI cards handle enabling antialiasing better than NVIDIA cards overall.
http://www.bjorn3d.com/read.php?cID=843
In the regular scores without AA and AF the X1800XT of course dominates.
As you can see there is no competition here. The X1800XT crushes the two other cards. With no AA/AF even the X1800Xl can almost keep up with the GeForce 7800GTX but as we turn on AA/AF it falls behind.