Intel Centrino mobile technology

 

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By Ben Hardwidge

Posted on 10 Mar 2003 at 16:25

You can say what you like about Intel, but you can't deny its marketing expertise. Brands like Intel Inside and Pentium have infiltrated the public mind at every level with their simple logos and huge advertising campaigns, but where do you go from there? Intel's next point of call is branding the whole mobile 'user experience', which it snappily calls Centrino.

Indeed, you don't just need the new Pentium-M processor to be in the Centrino gang. You also need Intel's latest 855PM or 855GM motherboard chipset and an Intel Pro Wireless LAN adaptor in tow. It's a bold step, which basically means notebooks can't use the Centrino brand unless all three components are combined. It's an interesting strategy in itself, but the new components also hold a few surprises.

The processor

Let's take the Pentium-M (originally codenamed Banias), which combines the best of the Pentium III-M and Pentium 4-M in a new chip. Like the Pentium III-M, it offers faster performance per clock, doesn't generate too much heat and can run at low voltages. But, like the Pentium 4-M, it also has a quad-pumped 400MHz front side bus and support for both SIMD and SIMD2 instructions to boost performance.

Intel hopes to speed things up even more with some extra cache. The Level 1 cache has been increased to 32Kb from the Pentium III-M's 16Kb, and the Level 2 cache has been increased to a huge 1Mb, which accounts for around 50 million of the 77 million transistors.

However, in order to save power, the full 1Mb of cache is only used when it's needed. When running on battery power, the chip only powers up the cache element it needs - Intel estimates that on average just 1/32 of the cache will be used.

But this is just one development of Intel's already impressive SpeedStep technology, and there are some other important changes. Previously, CPUs with Enhanced SpeedStep technology adjusted the frequency first, and then the voltage, but this meant the CPU had to stop what it was doing before it could drop down. Now the Pentium-M drops the voltage before the frequency, and it does this slowly enough for the CPU to continue what it's doing.

And the battery life is fine, especially under light use. Intel's claiming around five hours maximum battery life, depending on the notebook design, and the Acer TravelMate 800's rundown time of four and a half hours isn't far off.

The chip is being launched at clock speeds of 1.3, 1.4, 1.5 and 1.6GHz, with a 1.7GHz version scheduled for later this year. There's also a low voltage chip clocked at 1.1GHz and a 900MHz ultra low voltage part. The CPUs are currently manufactured on a 0.13micron process, but this is scheduled to move to 0.09micron later this year. Both FCPGA and FCBGA packages are available, which In conjunction with the low voltage could also mean we've got some high-powered ultra portable notebooks to look forward to as well.

Intel reckons a 1.6GHz Pentium-M will offer comparable performance to a 2.4GHz Pentium 4-M, but our 2D benchmarks are actually showing this to be quite conservative. With the 1.6GHz Acer TravelMate 800 scoring 1.4x, and the 2.4GHz Pentium 4-M-based Hi-Grade Ultinote M6600 (see issue 101, p108) scoring 1.19, the new Pentium-M is clearly the mobile chip of the moment, whatever its clock speed.

The motherboard chipset

Next on the Centrino checklist is the motherboard chipset, which comes in the form of the 855PM and 855GM - the latter offering integrated AGP 4x graphics. The graphics will have a core clock of 200MHz, as opposed to the 830M's 166MHz.