Detection, on 28 December 2012 - 14:21, said:
CFX only kicks in during fullscreen, so if you're minimising the game, or leaving it windowed to check if the 2nd GPU is being used, you`ll always miss it
You can right click the AMD logo icon on the taskbar near the clock and navigate through the menus to the AMD Crossfire part and tell it to show the CFX logo when CFX is in use
Also download GPU-z and see if it tells you that CFX is enabled, you can leave that open during the game and then check the usage of GPU 2 after the game
Problem Solved!
I hadn't noticed but in far cry, the screen was set to "borderless" rather than full screen, and for all intents and purposes, looked the same in game! works a treat now, and 2nd card defo working now... :-)