I bet those chips run hot, so they drop the turbo boost function. They're still much faster than C2D without the turbo.
All of the new Processors not only TurboBoost, but they also Hyperthread.
Actually, only i7 hyperthread. It's disabled on i5's.
i asked apple on the online chat thing and the person said no they do not, at least the 1.7 i5, which is what i asked about.