Intel has been doing this for ages. It may even be the primary reason why they came up with Turbo Boost. It's gotten a lot worse these days, as Turbo Boost can

Intel has been doing this for ages. It may even be the primary reason why they came up with Turbo Boost. It's gotten a lot worse these days, as Turbo Boost can add another Ghz on its own to the base clock, which allows Intel to keep base clocks very low, yet still claim its chips are as fast as if they always run at the peak Turbo Boost speed all the time (and that turbo boost running time has been shrinking every new generation, too).