Intel Centrino Guide

by Dustin Sklavos, California USA

INTRODUCTION

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:

1. Pentium M Processor
2. Intel Chipset
3. 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

BANIAS

• 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.

DOTHAN

• 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.

SONOMA

• 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
• PCI/AGP
• 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.

CONCLUSION

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.

 

Great job yet again!!

A Must-sticky post!

 

LOL, Intel aims to confuse, why they even handed out Centrino M&Ms a couple of years back...I kept scratching my head as to how they crammed the wireless card into such bite sized chocolate goodness:



http://www.notebookreview.com/default.asp?newsID=1739

 

Good overview of the ever changing Centrino technology, I think a lot of people need to read this as they often confuse the Centrino technology and call their processor Centrino Processors.

 

I'd rather have Intel include those then the Foil stickers

 

yea...me 2...and great job

 

Nice article to help people undo Intel's confusion which we've all become acustomed to.

BTW you called the CPU of the "Centrino 2/turbo" Sonoma (I guess to try and just find a name for it), while in fact it's just a Dothan with an uped FSB. I think the best solution for naming that intel could have taken was just adding a letter at the end of the speed/number of the processor. Just like in the days of the P4's northwood core, which passed thru A-B-C, as it's FSB went thru 400-533-800. But I guess this scheme won't go well with their marketing team. Adding a new cool name always sells more ... money rulez!

 

I did mention that Sonoma was essentially just a speedbump. It's my understanding that Sonoma is the term used for the Dothan with the 533 FSB, though people seem to use it interchangeably with the chipset, which is also called Alviso. Ultimately, this is where all the nomenclature confusion really gets wretched, because Sonoma is used for both the CPU and the chipset.

Unfortunately, they'd also already added letters to the GHz listings of the early Dothans to distinguish them from Baniases.

 

According to Intel:

Sonoma is the Platform which combines a Dothan PM with the Alviso chipset -- which essentially is just a 533FSB bumb.

The chipset is called "Alviso"
The CPU is Dothan
The platform that encompasses both elements is called Sonoma

hope that clarifies it a bit.

cheers,

yass

 

Does anyone know what happens if you put a 400Mhz FSB Pentium M into a 533Mhz i915 chipset laptop? I have a Quanta KN1 with a P-M 730 and was hoping that i could switch to the P-M 725 and it would run at 2Ghz. Any thoughts?

 

As far as I know, the chipset would detect the cpu and throttle it down to 400mhz FSB... I think I read somewhere that there was some sort of a "crack" on a hardware level (lead tracing a connection or two) that would fool the chipset to see it as a 533mhz chip, but I've never tried it. Search the forum here, I think I might even posted a link on that at one point...

cheers,

yass

 

I think that this should be "2915ABG - 802.11a ( 54Mbps), ..."

 

Sonoma is the codename of the Centrino suite, not the individual processor or chipset.

Sonoma suite = Dothan CPU (90nm) + Alviso chipset + ABG wireless

after Sonoma will be:

Napa suite = Yonah CPU (65nm) + Calistoga chipset + new type of wireless

Santa Rosa suite = Merom CPU + Crestine chipset (800MHz FSB) + new type of wireless

 

A few additions in case anyone cares. There are two variants of the 855: 855GM and 855GME. The GM is used with Celeron M or low-cost Pentium M systems and only support DDR266. The GME is the one that supports DDR333.

There are also variations in the 915 chipset. I have an Acer notebook here that according to the spec sheet has a "Sonoma chipset" with a 400 MHz FSB CPU and DDR2-400 RAM. But in fact the CPU is 533 FSB, but the RAM is DDR2-400. The next model with a higher price officially comes with a 533 FSB CPU and DDR2-533 RAM.

 

Would it be a good idea to combine a Dothan processor core, e.g., Pentium M 725A, with the Alviso 915 CHIPSET chipset and IMGA 900 to reduce heat and increase battery life? Compaq is offering that combination.

 

Yes - the 725A processor is an older model Pentium M, with a 400MHz Front Side Bus - it runs cooler and consumes less power than the 533MHz FSB model Pentium M's.

 

I must sound like a complete idiot and newbie right now, but what exactly is dual core? What is the differnce between this and like the hyper threading technology in the Pentium 4s??