With a LGA 1366 board you can only add upto 24 gB (6x4gb cards) all DDR3 memory sticks are supported except the very high frequency cards.
Go for corsair vengeance 3x4gB or 6x4gB as the triple channel will be used. Corsair vengeance says it is quad channel but I am using the same chipset with i7 980 x and got vengeance 6x4gB and it works like a charm.
If you are using more than 12 gB the only they will come into use. If you use less than 12 gB then the other 3cards won't do anything or increase the speed. Triple channel means that there are three memory controllers or three cards can be used simultaneously.