Dual channel asymmetric mode DH55TC

If you're asking whether or not you can use your 2Gb ram stick with your 4Gb ram...then the answer is no. Not unless you have 2 x 4Gb and 2 x 2Gb sticks with the same speed, cache, and latency, (Even then I wouldn't try it). Dual channel means that it can support pairs of the same type of ram at the same time. Now, the 4Gb RAM alone should be efficient enough by itself, depending on your OS and what you intend to use your computer for.