Naturally, each overclocked core pumps out more heat than it would do otherwise, but Intel insists that this won't adversely affect their longevity the way traditional overclocking sometimes can. This is because the Core i7 as a whole stays within its proscribed thermal limits.
Turbo Boost: up the frequency, a little bit for four cores...
Core and die temperatures are sampled constantly so the degree of overclocking will depend on moment-by-moment heat output, which is not only dependent on the CPU's speed and voltage settings but also on the efficiency of the cooling system plugged on top of it.
...further for two cores...
You might think that upping one or more cores' clock frequency would be a bad idea when the goal is to reduce power consumption as much as possible, the better to extend the runtime of the host laptop's battery charge.
...or even higher when only one core is scheduled
True, Turbo Boost does increase power draw, but Intel maintains that it's better to suffer a burst of power and allow the cores to complete their work more quickly than to take longer processing a task at a lower clock frequency.
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?