Portal specs question?

1.7GHz is not a processor speed. It's a clock tick rate (1.7 billion times per second). Portal's minimum system requirements call for a 1.7GHz Pentium 4 or better. The 1.4GHz Core i5 in the m11x is about four times as powerful as a 1.7GHz. It's a dual-core processor (basically two processors in one, so it can do nearly twice as much work), has hyperthreading (so each core can do 2 things at once), and it's a much newer and more efficient processor design so it can get more done in each clock tick. So yes, the m11x is powerful enough to play all those games that even call for a 3.0GHz Pentium IV or better. You won't start running into issues until you get to the newest games, which require a 2.4GHz Core 2 Duo or better, and even those, it should still be able to play although not as well.