14 DAY TRIAL // Intel calculates TDP (thermal design power) through a set of benchmarks that include some of the most troublesome desktop and notebook chips. The SDP thermal rating uses a lesser set of benchmarks though, more appropriate for thin tablets, to determine average power.
This, AnandTech explains, allows Intel to set power ratings depending on the tasks that chips are aimed for.
Thus, a new Y-series Haswell CPU that Intel is preparing could have two ratings.
If one were to, say, run FurMark on the chip, and the PC doesn't thermally limit the processor, the TDP will be of 11.5W.
When using the chip like in a tablet, however, the TDP is of 4.5 or 6W, depending on SKU. Lower than the marks specified on the slide above.
Intel will release the Y-series unit and (probably) advertise it under the 4.5W thermal envelope, in the hopes of scoring more tablet design wins.
No details exist on the chips, however, not even an actual name. Still, this all goes to show that Intel's efforts to make its chips more power-efficient are paying off.