PENTIUM-M

1/29/2005

The Pentium-M is Intel's processor optimized for laptop usage -- i.e. to minimize power usage and thus increase battery life. The Pentium IIIM and Pentium 4M were Pentium III and Pentium 4 CPUs with some modifications to reduce power consumption. The Pentium M is a complete CPU design from scratch focusing on low power consumption.

Major changes include more elaborate controls on CPU speed (SpeedStep) in order to avoid idling the CPU at high speed.which generates heat to no good purpose. In addition, the CPU operating voltage was reduced to 1.5 volts with future releases expected at 1.18 and 1.1 volts. Power consumed varies with the square of the voltage or current. The internal architecture was altered to include a 1MB cache, and an improved instruction stack manager and branch prediction algorithm. The changes resulted in an asserted 60% performance improvement over the Pentium 4M at the same clock.

In late 2004 Intel changed its roadmap for future CPUs to downplay the Netburst architecture used in the conventional Pentium 4. The Netburst architecture was originally planned to handle several years worth of improvements which would take it from the 3 plus GHz clock range to 10GHz. However, excessive heat and relatively poor performance attributed to the long pipeline in the Netburst CPUs have led Intel to phase Netburst out early and to build new desktop CPUs largely on the Pentium-M architecture. The code name for this effort is "East Fork".

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