you are listing a LGA 1155 board/CPU. On a sandybridge chipset/CPU you need dual channel ram...you should not go with the 3x4GB kits. So you will be limited to 2 or 4 dimms. better if you go 2 dimms on your memory controller. So 8GB would be better timing.
When you look at a motherboard that is dual channel you will see 4 ram slots , and when you look at a motherboard that is triple channel you will see 6 ram slots. Now when you buy your ram since you have a sandybridge cpu you have to buy dual channel ram which depending on the amount will either come as two sticks or four sticks. Some kits of 16gb will come as two sticks at 8gb per stick or it will come as four sticks ay 4gb per stick. If you already have ram and it is triple channel and you have three sticks you will have to consult your motherboards manual to see if it can be used. If you have not purchased the ram yet make sure you get the right ram for your MB. Dual channel and triple channel are different types of ram for different types of cpu's