Pentium M

The Pentium M^[1] brand refers to only two single-core 32-bit CPUs (with the Intel P6 microarchitecture of x86 microprocessors) introduced in March 2003 (during the reign of the Pentium 4 desktop CPUs), and forming a part of the Intel Centrino platform. The processors evolved from the last Pentium III branded CPU, and were intended for use in laptop personal computer only, thus the "M" moniker standing for mobile. The first Pentium M branded CPU, codenamed the Banias, was followed by the second one - the Dothan. After the Pentium M branded processors, Intel released the Core branded dual-core mobile Yonah CPU with a modified microarchitecture. Pentium M branded CPUs can be considered as the end of the Intel P6 microarchitecture.

Overview

The Pentium M represented a new and radical departure for Intel, as it was not a low-power version of the desktop-oriented Pentium 4, but instead a heavily modified version of the Pentium III Tualatin design (itself based on the Pentium Pro core design). It is optimised for power efficiency, a vital characteristic for extending notebook computer battery life. Running with very low average power consumption and much lower heat output than desktop processors, the Pentium M runs at a lower clock speed than the laptop version of the Pentium 4 (The Pentium 4-Mobile, or P4-M), but with similar performance - a 1.6 GHz Pentium M can typically attain the performance of a 2.4 GHz Pentium 4-M. [1]

The Pentium M coupled the execution core of the Pentium III with a Pentium 4 compatible bus interface, an improved instruction decoding/issuing front end, improved branch prediction, SSE2 support, and a much larger cache. The usually power-hungry secondary cache uses an access method to avoid switching on any parts of it which are not being accessed. Other power saving methods include dynamically variable clock frequency and core voltage, allowing the Pentium M to throttle clock speed when the system is idle in order to conserve energy, using the SpeedStep 3 technology (which has more sleep stages than previous versions of SpeedStep). With this technology, a 1.6 GHz Pentium M can effectively throttle to clock speeds of 600 MHz, 800 MHz, 1000 MHz, 1200 MHz, 1400 MHz and 1600 MHz; these intermediate clock states allow the CPU to better throttle clock speed to suit conditions. The power requirements of the Pentium M varies from 5 watts when idle to 27 watts at full load. This is useful to notebook manufacturers as it allows them to include the Pentium M into smaller notebooks.

Although Intel has marketed the Pentium M exclusively as a mobile product, motherboard manufacturers such as AOpen, DFI and MSI have been shipping Pentium M compatible boards designed for enthusiast, HTPC, workstation and server applications. An adapter, the CT-479, has also been developed by ASUS to allow the use of Pentium M processors in selected ASUS motherboards designed for Socket 478 Pentium 4 processors. Shuttle Inc. offers packaged Pentium M desktops, marketed for low energy consumption and minimal cooling system noise.

Pentium M processors are also of interest to embedded systems' manufacturers because the low power consumption of the Pentium M allows the design of fanless and miniaturized embedded PCs.

Sumber: http://en.wikipedia.org/wiki/Pentium_M