Consider this review an update to my previous one. The new M11x is cosmetically identical to its predecessor: It has the same screen, the same case, the same keyboard with AlienFX lighting, the same ports, the same weight...you get the idea. The big change is the switch from Core 2 Duo CPUs (my previous test unit had an overclocked Core 2 Duo SU7300) to Core i5 and i7 CPUs (this test unit has a 1.2GHz Core i7 640UM ultra-low-voltage CPU). It also has 4GB of RAM, a 500GB hard drive, and the same 1GB GeForce GT335M mobile discrete graphics chip found in the previous model. Prices start at $799, but the Core i5-equipped models start at $949, and our test configuration comes in at $1299.

The new CPU makes a significant difference in performance. The WorldBench 6 score increased from 77 to 91, and frame rates in games jumped anywhere from 10 percent to more than 25 percent, depending on the game. This leap comes at a cost, however. The integrated, nonremovable eight-cell battery in the original M11x provided almost 7.5 hours of battery life in our tests. This new test unit has the same battery, but it ran out of juice in about 5 hours. Because we weigh battery life heavily in scoring the performance of ultraportable laptops, this lower mark resulted in a very slight reduction in the overall performance score (from 84 for the original M11x to 83 for Revision 2). Be aware that this change in overall performance score is entirely the result of reduced battery life, and that the new M11x does indeed deliver considerably more power. If you opt for the Core i5 version rather than the Core i7 version that I tested, you'll probably get slightly longer battery life.

Though the old M11x had switchable graphics, a manual toggle controlled switching. The new systems incorporate nVidia's Optimus automatic graphics switching technology. When you use a program that might benefit from the discrete GPU (such as a game or a high-definition video), the graphics processor automatically kicks in, with no screen flicker, no pause, no discernable difference at all except for better performance. This is a great addition, but it introduced a minor technical problem that you, as a user, probably won't ever encounter. In running WorldBench 6, our test system would consistently crash during the 3ds Max tests. Updating to an early beta version of nVidia's upcoming driver solved the problem.

Overall, Alienware's update of the M11x makes the system even more attractive. The hit in battery life is substantial between my original test unit and this new one (I would probably opt for the Core i5 version to save a few watts), but 5 hours is still quite respectable for any laptop and you'd be hard pressed to find another system of this size and weight with such good game performance.