Welcome Newcomer!
The set would strongly suggest Dual-Channel
2 x - refer to your MOBO Manual for proper placement, and VERIFY that they are Certified or Tested. As "CORSAIR DOMINATOR 6GB
3 x 2GB DDR3-1066" suggests Tri-Channel or 12GB
6 x 2GB DDR3-1066 suggests Hexa-Channel.
Corsair Tested {Configuration/Memory Search} - http://www.corsair.com/
Certified {see your MOBO website}