Crysis is an HARD game
but yes 9 fps is low. Remove AA if you were using.
Watch for Running application behind the scene, CTRL-ALT-DELETE and see if you have any non wanted application running. It can be PSU related. Youv plugged the 2 6pin from the SAME PSu rail ? and you used 2 différent Rail. You can try switching PCI6 for testing, it can be a lack of power.