Im thinking of buying a 5870 to xfire with my current 5970. A few questions first. I have a micro ATX board, from experience, does anyone know if a 5970 and 5870 would fit? I know two 5870s will fit. Second, how easy would it be to xfire these two cards? Third, is a 875w PSU enough? Im running i7930, Asetek liquid cooling, 12gb ddr3 mem. Thanks in advance!