The point is, how many of your applications actually take up 4GB of memory? Except for a few (if running on a big server), there aren't very many. (Remember, you can still have 64-bit applications with multilib.) And when I read the first announcement, it already had significant performance improvements, and with further optimization it will be even more. Plus, it'll also save you memory. So until the day when most applications take up ~4GB, running x32 actually makes more sense.