Before the launch of the Pentium-M processors (the silicon brain behind the Centrino Mobile Technology), Intel has always been using their desktop-based processors for the notebook market. These so called 'mobile' processors are nothing more than your average desktop processors modified slightly to provide power saving features to cater to battery powered notebooks. It didn't take long for someone to figure out that this isn't the most efficient mobile processor in terms of battery consumption and heat emissions - the two major bane for notebooks. To understand this inefficiency, you'll need to appreciate the intricate details as to why a desktop processor isn't a perfect model for mobile computing and why Intel took the effort to design a processor from the ground up to cater solely to notebooks.
When people talk about processors for desktops, they talk about raw processing power, and more often than not, the first word to pop up is the clock speed or Megahertz (MHz). In the early age of personal computing, clock speed or Megahertz is used to determine the performance (and the overall price of course) of a personal computer. The general rule of thumb was that the higher the advertised number, the faster and better computing performance you'll get. For example, a 2.4 GHz Pentium 4 goes through 2,400 million cycles every second. From an arithmetic perspective, this mind-boggling number represents some very powerful and impressive computing performance indeed. But from a microprocessor level, this is just part of the performance equation. What most people tend to overlook even up till now are other attributes found within a microprocessor that sums up a processor performance and capability.
Bus architecture, pipelines, and cache in a microprocessor are some of the key performance elements to take note in the technical specifications of microprocessors. But how does all these relate to the performance variation between a desktop processor and a mobile processor? To be honest, all the above mentioned elements play significant roles in the architecture of a processor and its intended application area. But before we venture into the various processors for mobile platform, you'll need to understand the nature of these elements first.