by Dustin Sklavos, California USA
Intel’s Centrino platform is, as of the time of this article, the premier notebook platform. Essentially a marketing initiative, the Centrino brand denotes three things:
- Pentium M Processor
- Intel Chipset
- Intel Wireless
If all of these criteria have been satisfied, your notebook is under the Centrino brand. In case you missed the marketing logo Intel uses for this, it’s shown below:
Unfortunately, we’re on the third generation of Pentium M, the second generation of chipset, and the third generation of wireless. While Intel hasn’t muddled the issue quite as well as AMD can (feel free to explain to me why one Mobile Athlon 64 3700+ is faster than the other), it’s gotten pretty ugly. Ugly enough that this guide is needed.
So while Centrino still sports the best efficiency and the best battery life, it’s not quite what it used to be.
In this guide I’ll break down the three different versions of the Pentium M, the two different chipsets, and the three different wireless cards, and I’ll tell you how you can differentiate them at the store.
What I’m not going to review are the Low Voltage and Ultra Low Voltage variants. Most of what I say will apply to the Low Voltage variants, while the Ultra Low Voltages still by and large use the Odem chipset and run at the same 400MHz front side bus regardless of core.
CENTRINO VS. CENTRINO “2”
The biggest distinction that should be made is this one: the first two generations of the Pentium M (Banias and Dothan) used the 855 mobile chipset (Odem), while the third generation (Sonoma) used the 915 mobile chipset (Alviso).
This is an important distinction to make. I’ve read many articles on other sites that suggested the new Centrino platform should’ve been labeled differently and I concur. It has more raw performance, but the battery life suffers. Maybe they could’ve called it “Centrino Turbo” or “Centrino Pro” or something? Or just plain ol’ “Centrino 2”?
THREE DIFFERENT PROCESSOR CORES
- Distinguishing Characteristic: No model number, or model number 705.
- Process: 130 nm
- Highest Speed: 1.7 GHz
- Front Side Bus: 400 MHz
- Cache: 1 MB
Banias is the original core for the Pentium M, and is probably the least efficient of the three. Battery life wise, it sits right in the middle of the other two cores. Banias is probably the least preferable of all of the cores. The Banias core’s average TDP (Thermal Design Power) is 24W.
- Distinguishing Characteristic: Model number ends in 5 (except 705), clock speed sometimes noted with an “A” (i.e. “1.6A GHz”). Low Voltage models are 718 and 738. Ultra Low Voltage models are 713, 723, and 733.
- Process: 90 nm
- Highest Speed: 2.1 GHz
- Front Side Bus: 400 MHz
- Cache: 2 MB
Dothan is the revised core for the Pentium M, and is my favorite of the lot. While not offering the pure performance of the Sonoma cores, it’s the most efficient by far. While improving certain features of the Banias core and shrinking down the die size, it also reduced its TDP to a very impressive 21W.
- Distinguishing Characteristic: Model number ends in 0. Low Voltage model is 758. Ultra Low Voltage model is 753.
- Process: 90 nm
- Highest Speed: 2.26 GHz
- Front Side Bus: 533 MHz
- Cache: 2 MB
Here’s where it gets confusing. Some people call the chipset Sonoma; some call the core Sonoma. I’m calling the core Sonoma and the chipset Alviso, which was the chipset’s development name. Sonoma is, in my opinion, where Intel might have dropped the ball, or at least fumbled it. It’s an incremental speed bump of the Dothan core and nothing more, bringing the front side bus up to 533 MHz. Unfortunately, this also raised the TDP to 27W, a full 22% higher. This is part of the reason Sonoma based Centrino notebooks have worse battery life than the Dothans.
TWO DIFFERENT CHIPSET PLATFORMS
There are currently two main chipsets in circulation on the Centrino platform, and they’re most easily distinguished by which integrated graphics core they use. Alternatively, if a notebook uses DDR2 instead of conventional DDR, you can be sure it’s an Alviso.
855/865 CHIPSET (ODEM)
- Single-Channel DDR333 RAM
- SoundMAX Audio
- Intel Extreme Graphics 2
The 855/865 is a wholly unremarkable chipset – it was when it debuted, even – but is also the chipset of choice for battery life, and was the sole notebook chipset for the Pentium M until Sonoma and Alviso were debuted. The Intel Extreme Graphics 2 ensures you’ll never play anything beyond Quake 3 generation (for reference, UT2K4 ran better in software on my ULV 1GHz Banias, but still was unplayable).
For the most part this chipset was “passable” and had basic features, but consumed very little power and was an excellent choice, which is why it is still used for inexpensive or power-efficient notebooks today.
915 CHIPSET (ALVISO)
- Single-Channel DDR333/400 RAM or Single/Dual-Channel DDR2 RAM
- PCI Express
- Azalia 7.1 Audio
- Intel Graphics Media Accelerator (GMA) 900/950
This is the other reason why newer Centrino notebooks run hotter and eat more juice than older ones. The memory controller consumes more energy, as does the GMA900, as does the PCI Express bus. Though PCI Express and DDR2 were theoretically supposed to reduce power consumption, this hasn’t been exactly the case.
Of course, the flipside of this is that the 915 offers higher performance than the 855/865, and the difference in battery life, while not negligible, is acceptable (usually about a half hour or so) for the increased performance and superior audio controller. The GMA900 is, while still undesirable, a vastly superior GPU to the Extreme Graphics 2, and will actually play most modern games (excluding resource hogs like Doom 3). It’ll play them at the lowest settings, but they’ll run.
THREE DIFFERENT INTEL WIRELESS CARDS
The third piece of the equation is, mercifully, the simplest one. For what it’s worth, Intel’s wireless controllers are widely respected and rightfully so. I’ve used other brands (Netgear, Broadcom) and have never been as happy as I was with Intel’s.
These are pretty easy to understand, so I’ll summarize their features.
- 2100B – 802.11b 11Mbps only.
- 2200BG – 802.11b (11Mbps) and 802.11g (54Mbps).
- 2915ABG – 802.11a (11Mbps), 802.11b (11Mbps), 802.11g (54Mbps), support for future 802.11e, h, i, etc.
Essentially they just get better and better, but any one of them is plenty usable and shouldn’t really be a deciding factor beyond wanting one with 802.11g, which is standard these days. I’m sure I missed an adaptor or two here and there, but these are the three main ones.
THE FUTURE: YONAH, MEROM, AND BEYOND
Dual core is the big catch phrase among the CPU developers right now. Finding themselves hitting a performance wall with single core chips, they’re now pushing towards multi-core processors. That would be all well and good, but the benefits of multi-core for the average user haven’t totally panned out, as consumer applications by and large – and especially games – aren’t written to utilize two cores, so you really only get the performance of one.
Intel’s next Pentium M is code-named Yonah, and it will be dual core. I’ve heard it will be 64-bit enabled and I’ve heard it won’t be; I’m leaning heavily towards “won’t be,” as that seems to be the key feature of the Merom core.
The Yonahs will appear at the end of 2005 at the earliest, with Merom showing up sometime in 2006. Are either of these worth waiting for?
Probably not. I suspect we’ve hit the zenith of Pentium M’s battery life, though there are rumblings that Merom will actually have superior power consumption to even Dothan. Either way, neither of these bumps merit the wait. If you must have 64-bit right now, Turion 64 and Athlon 64 are both excellent choices. Dual core is a bit trickier, but isn’t a necessity and likely won’t be for a few years except in a few small, isolated cases.
Intel’s done a great deal to muddy the waters regarding the Centrino platform; if they’d just switched Sonoma/Alviso’s name to something like “Centrino Turbo” or something, it’d be a lot easier to tell the platforms apart.
That said, the big winner for battery life is Dothan with Odem, while the big winner for performance is Sonoma with Alviso.
Intel did the public a wonderful service in bringing notebook computing out of the dark ages with the Centrino platform; now if they could just get rid of the confusion surrounding the platform, we might all be a lot happier.