Intel's Centrino CPU (Pentium-M): Revolutionizing the Mobile World
by Anand Lal Shimpi on March 12, 2003 6:10 AM EST- Posted in
- Laptops
Looking at the way mobile CPUs have been developed in the past, it's very clear that this isn't the right way to solve the problem of producing a high performance, low power CPU.
AMD or Intel would simply take a desktop CPU, scale it down (in both frequency and voltage), make it go to sleep as much as possible and call it a mobile processor. This worked for a while when we were dealing with relatively low power desktop CPUs like the Pentium III, but take a look at the power requirements of a mobile Pentium 4 running at 2.4GHz and you'll quickly come to the conclusion that there has to be a better way.
Now look at AMD's plans with their mobile Athlon 64; in this case they're taking a server CPU that was already scaled down to be a desktop part and doing whatever it takes to make it a mobile processor.
Neither AMD nor Intel's approaches to mobile CPU and platform architecture will work, and it's very clear the reasons why; other than reducing clock speed and attempting to keep voltages as low as possible, the CPUs are still architecturally identical to their desktop counterparts. There are always going to be parts of the chip that aren't optimized for low power operation, making the CPU far from well designed for mobile applications. When the architects at AMD and Intel are designing their desktop or server processors, they aren't concerned with battery life on a notebook, and thus the vast majority of the decisions they will make will be insensitive to the needs of a mobile CPU.
Moving beyond the CPU, the chipset and rest of the platform are also taken directly from the desktop world. The North Bridge in today's notebooks is identical to what we see on desktops, and with the amount of traffic that goes through that chip, there's definitely a lot of wasted power.
The amount of inefficiencies in current mobile architecture is astounding when you think about it, and after today, you'll understand how they're all going to go away…
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zigCorsair - Wednesday, July 14, 2004 - link
I thought it was a very informative article. Of course, I'll be upset if it's biased, but being a master's student in CS, many of the exact details I was looking for were in here, and for that I say thank you.Zebo - Monday, May 10, 2004 - link
I don't see whats so impressive. An athlon mobile 2600/2800 xp 35W version, which runs ~2000Mhz will kill these. To little to late.Anonymous User - Wednesday, September 10, 2003 - link
how the hell could this be a balanced and informative article when in their own analysis they ignored their own data?There is no mention of the anamolous nature of the BAPCO test..absolutely NOTHING...
Its enough for me to question the competency of this site...and even to the point where I suspect that certain unethical compromises have been made.
Anonymous User - Wednesday, September 10, 2003 - link
Yeah, I agree with Sprockkets... same reason Athlon XP loses to the P4 in this benchmark... someone was trying to make the P4 look better, and everything else look worse. Now all the sudden, this new great CPU is getting it's but kicked because of all the P4 optimizations (and probably non-P4 deoptomizations).sprockkets - Tuesday, September 9, 2003 - link
I wonder why the P4 trashes the PM on Content Creation Performance and nothing else? Maybe it's the stupid skewing toward the P4. Why else would it lose here and kick butt everywhere else? www.theinquirer.net has an article which brought this to readers attention.Anonymous User - Thursday, August 21, 2003 - link
"Without a trace cache, the design team was forced to develop a more accurate branch predictor unit for the Banias core. Although beyond the scope of this article, Banias was outfitted with a branch predictor significantly superior to what was in the Pentium III. The end result was a reduction of mispredicted branches by around 20%."Wouldn't he mean that the branch predictor was superior to the P4?
Anonymous User - Tuesday, August 19, 2003 - link
looks goodAnonymous User - Friday, August 8, 2003 - link
An outstanding well balanced article, after this read I feel I really know about Centrino. Thanks