Hello, I just purchased a third monitor identical monitor so that I can hook up eyefinity. I know with a single 5870, I need the active display port adapter. However, I am running 2 -5870's in crossfire. With the latest 10.2 drivers, can I just connect the third monitor to the second 5870, or do I still need to connect all three monitors to the primary card?
You need to connect all monitors to the first card in a crossfire setup. Also that 3rd monitor need to be connected to the DisplayPort output. Which you will need a DP to DVI/HDMI ($100) adapter or DP to VGA (~$20) adapter if you dont have a native DP monitor.