Since this discussion will likely be of interest to many, let's quickly point out here what people mean here by a couple of key terms:
TDP a.k.a.Thermal Design Package
This is Important to understand.
A processor operates with a set of given limitations on its power consumption and heat generation. When these limitations are about to be exceeded, the power of the CPU is limited to remain within the set parameters.
The limitations are typically based on;
- Average power consumption
- "Skin temperature" (how hot the surface of the device gets)
- CPU temperature
So if a CPU is classified at, e.g. 45W, it means the system will not let the CPU consume more than 45 watts of power in average.
As such, if a CPU is always 100% cooled, it can operate as fast as the power consumption limitation let's it. So a 4.5W CPU can consume 4.5 watts 100% of time. Correspondingly, a 45W CPU can consume 45W of power on similar scenario.
But any of these factors can limit the CPU. So even if the CPU has not consumed more than the maximum allowed amount of power (e.g. a 4.5W CPU is consuming only 3.5W), it can still be limited (called throttling) by the heat limits - either skin temperature or the CPU temperature.
Any and all of these factors will affect the performance of a particular CPU.
Intel's 4.5W processors. Built for thin and fan-less designs. Operate with lower base frequencies than their 15W counterparts, but can generally turbo boost to same level than them.
Actively cooled (normally with fan(s)) 15w CPUs. Generally have higher base speeds than Core i-Y. Compared to the fan-less designs, produce more heat and noise, but can also maintain higher average clock speed
Since tasks that are typically needed from a CPU are these days such that speed is needed at a particular time, but not all the time, Intel has designed a "Turbo-Boost" capability to the processors.Turbo-Boost effectively let's the CPU operate above the power consumption threshold set - essentially consuming more power -to finish a task quickly, and then start idling again.
Smart, isn't it? Its like a sports car rallying to pass the crossing while the lights are still green, and them switching back to idle revs to roll forward.
This can be done as long as the CPU consumes the certain set amount of power in average and doesn't overheat.
Thermal-design and power consumption parameters affect the turbo-boost. That's exactly why the community decided to let our users configure the TDP of our Core Y CPU from BIOS. Some users are fine exchanging more heat and lower battery life to higher performance. That's why TDP adjustments are to be enabled from the V's BIOS (we are still working on that).