Memory upgrade for Alienware Aurora R3

Hello,

I bought recently an Alienware Aurora R3 with 16 GB ram at 1333, but I can't say i'm very happy with it. The memory is Samsung, has high response time and well, it's Samsung. I'm thinking on upgrading the RAM to 8gb/12gb 1866 Mhz or 2000 Mhz, but I don't know if the motherboard supports 2000 (1866 i know it does) and also, I see on the market are different setups on double channel/triple channel and I don't know what are the advantages of either or if the motherboard supports both dual and triple channel.

Any advice is greatly appreciated.