The Sager would definitely be considerably quicker- the Alienware has a mobile Core i7 + a single mobile GPU, whereas the Sager has a desktop Core i7 (Massive performance boost over mobile) and mobile dual GPUs (Ideally, 50% faster). You don't usually say this, but the Alienware is more portable and will probably generate less heat, while the Sager will be considerably faster, and probably run hotter under load.