That actually kicks serious butt!
http://www.ewiz.com/detail.php?p=MB-A8R-MVP&c=fr&pid=78...9ba68853f0bc28693feb
Check this review out:
http://www.anandtech.com/printarticle.aspx?i=2617
I have been reading up on the DFI Crossfire offering on their forums and it has been plagued with issues. Plus, the X1800XT's don't seem to work well at all with it. Actually, the X850XT PE and an X850 control card in Crossfire mode performs better than the X1800XT does for some reason on the DFI board.
Well, that just isn't the case with this Asus A8R-MVP. I have been impressed with the 7800GTX's numbers in SLI form and am glad to see the X1800XT perform up to its potential and actually rival the 7800GTX SLI.
I believe I may just go ahead and order this board after I read a couple more reviews and confirm what AnandTech has found. I just don't think there will be another well known and respected mobo manufacture offer a Crossfire capable mobo, especially with the review this one has gotten, at a price like this.

