Pentium M
From Wikipedia, the free encyclopedia
| Pentium M Central processing unit |
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 Pentium M 730 core Dothan |
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| Produced: | From 2003 to now |
| Manufacturer: | Intel |
| CPU Speeds: | 900 MHz to 2.26 GHz |
| FSB Speeds: | 400 MT/s to 533 MT/s |
| Process: (MOSFET channel length) |
0.13 µm to 0.09 µm |
| Instruction Set: | x86 |
| Microarchitecture: | P6 (Pentium M variant) |
| Sockets: | |
Cores:
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Introduced in March 2003, the Pentium M is an x86 (Intel P6) architecture microprocessor designed and manufactured by Intel and forms part of the Intel Centrino platform. The processor was originally designed for use in laptop personal computers, thus the "M" for mobile. It was codenamed "Banias" before its introduction.
Contents |
[edit] Overview
The Pentium M represents a new and radical departure for Intel, as it is 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 couples 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.
[edit] Banias
As the M line was originally designed in Israel, the first Pentium M was identified by the codename Banias, named after an ancient site in the Golan Heights. Given the product code 80535, it initially had no model number suffix, but was later identified as the Pentium M 705. It was manufactured on a 130 nm process, was released at frequencies from 1.3 GHz to 1.7 GHz using a 400 MT/s FSB, and had 1 MiB of Level 2 cache. The core average TDP (Thermal Design Power) is 24.5 watts.
The CPUID signature for a Banias is 0x69X.
[edit] Dothan
Intel launched its improved 80686 Pentium M, formerly known as Dothan, named after another ancient town in Israel, on May 10, 2004. Dothan Pentium M processors are among the first Intel processors to be identified using a "processor number" rather than a clockspeed rating, and the mainstream versions are known as Pentium M 710 (1.4 GHz), 715 (1.5 GHz), 725 (1.6 GHz), 735 (1.7 GHz), 745 (1.8 GHz), 755 (2.0 GHz), and 765 (2.1 GHz).
These 700 series Pentium M processors retain the same basic design as the original Pentium M, but are manufactured on a 90 nm process, with twice the secondary cache. Die size, at 84 mm², remains in the same neighborhood as the original Pentium M, even though the 700 series contains approximately 140 million transistors, most of which make up the massive 2 MiB cache. TDP is also down to 21 watts (from 24.5 watts in Banias), though power use at lower clockspeeds has increased slightly. However, tests conducted by third party hardware review sites show that Banias and Dothan equipped notebooks have roughly equivalent battery life.[citation needed]
The processor line has models running at clock speeds from 1.0 GHz to 2.26 GHz as of July 2005. The models with lower frequencies were either low voltage or ultra-low voltage CPUs designed for even better battery life and reduced heat output. The 718 (1.3 GHz), 738 (1.4 GHz), and 758 (1.5 GHz) models are low-voltage (1.116 V) with a TDP of 10 W, while the 723 (1.0 GHz), 733 (1.1 GHz), and 753 (1.2 GHz) models are ultra-low voltage (0.940 V) with a TDP of 5 W.
Revisions of the Dothan core were released in the first quarter of 2005 with the Sonoma chipsets and supported a 533 MT/s FSB and XD (Intel's name for the NX bit) (and the PAE support required for it was enabled, unlike earlier Pentium Ms that had it disabled). These processors include the 730 (1.6 GHz), 740 (1.73 GHz), 750 (1.86 GHz), 760 (2.0 GHz) and 770 (2.13 GHz). These models all have a TDP of 27 W and a 2 MiB L2 cache.
In July 2005, Intel released the 780 (2.26 GHz) and the low-voltage 778 (1.60 GHz).
The CPUID signature for a Dothan is 0x6DX.
[edit] Core Solo and Core Duo
The next generation of processors using the Pentium M microarchitecture, codenamed Yonah, was released under the Intel Core brand, as Core Solo and Core Duo.
[edit] See also
[edit] External links
- Intel's Pentium M Homepage
- Intel's list of all Pentium M variants
- Intel Processor comparison table
- Intel Embedded Solution Directory (miniature fanless Pentium M computer module)
- Homepage of the software "Notebook Hardware Control"
- Homepage of the Software "Linux-PHC" to undervolt a Pentium M with linux
- Intel Pentium M technical specifications
- Yonah details from X86-secret (french translated to English through google)
- AnandTech: Yonah Performance Preview
- SpeedswitchXP - CPU frequency control for notebooks
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