I feel the need for SPEED!
In its attempts to develop a good notebook processor, Intel created four chips that had similar names and often confused people. The Pentium 3 Mobile (early 2001), the Mobile Pentium 4-M (early 2002), the Mobile Pentium 4 (mid-2002), and the Pentium M (early 2003) were all different microprocessors. In the end, it was the Pentium M that won the battle to be notebook kingpin.
Centrino
The Pentium M became the basis of Intel's current Centrino family of chips. It had one great advantage over all of Intel's other mobile processor designs---it was designed from the ground up to be used in a notebook computer. Moreover, it was designed as part of a package of chips; Centrino is not only a processor but also a chipset (the controllers for all the components in the notebook) and a wireless communications chip. The Mobile Pentium 4 had none of these advantages.
Architecture
The Mobile Pentium 4 was built from the Pentium 4 chip. It was more of an attempt to make an existing chip work in a system with stringent requirements as opposed to a design specifically for notebooks.
The Pentium M, by comparison, started with the earlier Pentium 3 chip, but was changed considerably. Rather than a low-power adaptation of the existing chip, it was completely reworked to get the results the designers wanted.
Speed
The Pentium M is the fastest mobile chip Intel has made. These speed increases aren't a matter of clock speed, but of how data is processed during each clock cycle. For example, according to notebookcheck.net, the Pentium M was "very fast per megahertz" compared to its other mobile chips. Tests at the University of Pennsylvania back that assessment; Penn Computing noted that "Pentium M chips are SIGNIFICANTLY higher in performance than Mobile Pentium 4 chips at any given clock speed" (Penn Computing's emphasis). Testing has even shown the Pentium M to be faster than some of the desktop Pentium 4 chips.
Heat
Mobile Pentium 4 chips gave off much more heat, due to their likeness to the power-hungry Pentium desktop chips. Some models of the Pentium M use as little as 5 watts. But even a typical Pentium M installation‚ drawing about 25 watts, needs less than a third the power of a comparable Mobile Pentium 4. In fact, when Hexus.net reviewed the Pentium M 735 chip, they claimed it could run in "free air"---with no fan at all.
Bus
The front-side bus (FSB) is the series of connections between the microprocessor and memory controller chip that lets the various components on the motherboard communicate with each other. Both the Mobile Pentium 4 and the Pentium M use the same FSB of the Pentium 4. Most chips use either a 400- or 533 MHz bus.
Tags: Mobile Pentium, Pentium chips, Pentium chip, clock speed, existing chip, Mobile Pentium chips