Well, I have a v4800 myself and was so close to buying another one for the sake of crossfiring, however, I kept getting mixed input on whether or not it would be possible. Some sites said yes, some said no, but I could never find anything "official", so I just decided to call AMD myself and take the hassle out of spending all that time googling for something I could never find. Kind of confusing about disabling it, yeah, but I suppose that's how they would sucker you into going for a higher priced card in the FirePro line.