Around the launch of the Alienware M17x R3, Alienware essentially bifurcated its high end notebook offerings into single-GPU (the M17x R3) and dual-GPU (the M18x). The M17x R3 was slimmed down from its beefy predecessor and the M17x actually remains one of the sleeker desktop replacement notebooks available. The M18x had to take its place at the top of Alienware's stack, then, as their contender for the most powerful gaming notebook on the market. That contention continues with the M18x R2, which like the M17x R4 we recently reviewed is more of an incremental update than a fully-fledged new design. The R2, like the R4, brings with it an Ivy Bridge CPU and a pair of Kepler-based NVIDIA GeForce GTX 680M GPUs in SLI. As...