Neither will softmod, I believe.
The only Ati that will softmod is the Sapphire X800GTO2, and it's pretty much made to softmod from 12 to 16 pipes.
I hear you can softmod X800XL's to X800XT's in some cases, but all that really does is overclock, no pipes are added.
From what I've heard, anyhoo.
<b>Geforce <font color=red>6800 Ultra</b></font color=red>
<b>AthlonXP <font color=red>~3300+</b></font color=red> <i>(Barton 2500+ o/c 412 FSB @ 2266 Mhz)</i>
<b>3dMark05: <font color=red>5,275</b>