how does turbo boost with i7 3rd gen laptop differ from the desktop counterpart?

I hear the turbo boosts in older i7 mobile cpus were misleading. the more cores active, the lower the turbo boost is. is this true with the i7 3rd gen laptop cpus?

It's true for laptops and desktops the more cores that are active the lower the turbo boost for 3Gen 2.0 turbo boost.

There are a couple things that set the speed for turbo boost on our processors. The first is the number of cores that are active (doing something). The second is the temperature of the processor. So while you should always see some performance gains from turbo boost on the Intel® Core™ processors the amount of the boost can change based on what you are doing.

As a general rule the turbo boost on the 2nd and 3rd generation Intel Core mobile processors will yeild a higher boost then the desktop models (Intel Core i7-3720Qm can reach up to 3.6GHz from 2.6GHz, the Intel Core i7-3770 can reach up to 3.9GHz from 3.4GHz).

I wouldn't say misleading.
They're designed to bump the multi a lot with a single core and less with every additional core that is running.
That's what they say they'll do, too.