Hi All I have 2 pcs, 1 with a 1900XTX 512MB, and one with a 1900XT 512MB Both different brands, I have read people as having an XTX Master card an an XT in crossfire mode and I was wondering is it actualy possible for me to crossfire to the 2 different cards?

Do they have to be the same model, e.g 2x 1900, 2x1800 as well or could you have say 1x 1900 and 1x1800?