Powering down the processor more quickly should help keep the cooling fan running less frequently. No one likes a noisy notebook, and since Turbo Boost operates within the existing CPU thermal envelope, the fan shouldn't need to spin higher, either.
We won't be able to say how well it works until real-world tests are conducted - watch this space.
Getting cores into an idle state slashes power consumption
Turbo Boost operates independently of the operating system - unlike SpeedStep and HyperThreading, for example - so it'll benefit Windows, Linux and Mac OS X users equally.
Windows Vista currently is well able to make use of HyperThreading and SpeedStep, but Windows 7 adds some new tricks to make smarter use of the available processing resources, the better to minimise power drain when performance isn't paramount.
Using a technique called thread-parking, Windows 7's scheduler is, Microsoft claims, better able to allocate resources than Vista's, switching threads in flight from virtual to physical cores so those threads can complete more quickly. It's about ensuring the OS understands there's a difference between physical and virtual cores rather than simply seeing a Core i7 as an octo-core chip, as Vista essentially does.
When all the physical cores are busy, then 'parked' virtual cores are given tasks to run. Again, this is about using the fastest resources first in order to complete work more quickly and then power down cores to preserve the battery charge. It should also make the system more responsive.
Trying to hold processing resources in reserve this way means that they're ready to be called upon when a peak in demand occurs, ensuring that the user interface doesn't freeze when other tasks are grabbing lots of CPU cycles. Of course there are instances when the load patterns means this is going to happen anyway, but smarter scheduling and the extra headroom provided by TurboBoost should minimise the frequency of such moments.
Its all in the leakage...
Modern <=90nm silicon processes no longer lose most of their energy in switching gates (more is the pity) but in simple leakage across the transistors. This exponentially increases as things are made smaller and exponentially increases with temperature. The energy loss happens even if the gates are "idle"!
Fast logic transistors == horrible leakage
So to solve this problem engineers add header and footer power switch transistors (bad logic transistors, so slow) to turn "hard off" whole sections of circuit. This Intel strategy means Intel can have its cake and eat it too.
Running some cores faster and turning "hard off" others saves all that lovely "idle" leakage. The thermal mass of the packaging and die will prevent excessive temperature rises in that one core saving exponential thermal effects.
RE: Physical cores vs. Virtual (hyperthread) cores #
If Windows sucks because it is just now releasing an OS that differentiates between physical and virtual cores, where does that leave Mac? The article handed you a pro-Linux talking point on a silver platter. Did you miss the preceding paragraph about Apple’s grand central dispatch? If your thinking was less Microsoft-centric your OS of choice might be taken more seriously.
Sounds more like they underclock under normal circumstances and return to normal speed when needed.
The turbo boost sounds more like a marketing gimmick to me - 'slows down to cool down' won't sell as many chips!
It very much depends on use case & how well the power is managed. If you double the clock & run for half the time then yes energy used is same or greater (depending on voltage) but, with good power managment, if you run fast there is more opportunity to sleep longer & deeper.
OK, I'll bite
Where do you get that overclock widget?