Notebook with 1.8ghz i7 chip with "turbo," vs desktop 2.8ghz i7

The Sony i7 notebooks have a base speed of 1.7ghz or 1.8gzh, coupled with a "turbo boost" that is supposed to hype the speed to over 3.0 ghz. This compares to desktop i7 chips that run at 2.8 ghz or, for more money, maybe 2.9 ghz. Presumably, the notebook chips use a lower base speed to conserve battery juice and expell less heat.

But what are the performance trade-offs? I'm not aware of any Tom's Hardware type charts that compare the operations of the two types of chip accross multiple software applications.

Anyone have a hunch whether the notebooks with the i7 chips and the "turbo" feature work faster, slower, or about the same as the other ones when, say, encoding AVCHD video? Does the turbo work best in short spurts, perhaps failing or causing damage if in gear all the time? Is it like overdrive on a car, useful in a steady cruise, but not for a long hill climb?

 

Is I know, the turbo boost feature of intels mobile processors means that when your applications just use one core, this core can be overclocked while the other core remains on low freq. Also both cores can be boosted when in temperature and of course in designed tpd range. I use the i7-620m dual core processor. Its standard speed is 2.66ghz and regularly it is boosted to ~3ghz without problems. In comparisons you can see that with that it is at least as fast as the older C2D T9900 with 3.06ghz and w/o turbo boost (plus the architecture improvements of the i7 over the c2d). On single core mode the 620m is capable of boosting one core to 3.3ghz.

You have to say that the i7 m's have a good energy management and clock dynamically at maximum possible ratings, if you dont need the power, they clock down and save you battery juice.

The 1.8ghz i7 you are talking about is one of the Low or Ultra-Low-Voltage models. They are clocked down and way slower than the standard i7 mobiles but have 10 or 18W TPD for long runtimes.