so i got the upgrade bug and i am thinking about building a pc ... right now i have a hdmi ati 4830 1gb in my system i want to build a new pc and i want a 4850x2 with a native hdmi port but they do not make them could i crossfire the 2 cards and use the hdmi out on the weaker 4830 and still get same performance or does the stronger card need to be on top?