Best thing you can do to get crossfire working is to load up radeon pro and force Lost planet profile.
http://forum.1cpublishing.eu/showthr...t=23604&page=2
COD doesnt use crossfire properly by default its only using 50% of each GPU compared with 100% of 4GPUs in my rig with the lost planet profile.
PS. Turning on "Disable API monitoring" under settings for radeon pro stops the menu corruption in game.