Ill give that a go tomorrow with 8.6 and 4870 in COD4.
Given your experience SKY with XF on 8.7 is it worth moving from 8.6 cf? Looking forward to the Xf review anyway...well hopefully not too scathing. Are you using the DFIX38 board-I know they had issues with 3870X2 but not heard anything about 2x 3870's or 4870's.
Maybe better 8.8 drivers for August will move things along otherwise the second 4870 on its way is going to have to find a new home
EDIT:Also heard about 3D to 2D issues with cf?