centrino is not a CPU per se but a combination of CPU, chipset, and wireless.
its a marketing term. meant for mobile systems centrino debuted as an all in one "marketing" solution for laptops promising longer batter life than others. low power chipset, low power CPU and low power networking all combined to make centrino.
it has since its debut changed to reflect the current laptop ecosystem and updated wimax chips https://en.wikipedia.org/wiki/Centrino
the low power part of the equation is why centrino has the rep it does.