Intel's Pentium M on the Desktop - A Viable Alternative?
by Anand Lal Shimpi on February 7, 2005 4:00 PM EST- Posted in
- CPUs
Final Words
As a mobile processor, the Pentium M cannot be beat - we've actually seen why, even in this comparison today. With a highly power optimized architecture, the Pentium M continues to deliver performance that is competitive with other mobile CPUs on the market. The problem is that in the transition to the desktop world, its competitors get much more powerful, while the Pentium M is forced to live within its mobile constraints.Think of it like this - the Pentium 4 and Athlon 64 are clearly the stronger chips of the three, as we have proved in today's review. However, in the mobile world, the Pentium 4 and Athlon 64 are often castrated or limited either by low clock speeds, single channel memory controllers or more physical constraints (e.g. you can get desktop P4 performance, but only in a 13lbs notebook). The Pentium M however, was designed from the ground up with these types of constraints in mind, and thus, excels quite well with them in place. Begin to remove the constraints and the Pentium M appears to be much less impressive compared to the Pentium 4 and Athlon 64 because the chip was designed to perform best with those constraints in place. The very low latency 2MB L2 cache is a prime example of this design mentality. A large L2 cache reduces the need for a high bandwidth memory bus, and making it low latency means that the CPU is even less dependent on such a bus.
The fact of the matter is that the Pentium M, while excellent as a mobile CPU, isn't the response from Intel that everyone is hoping for. The successor to the Pentium 4 won't be an architecture derived from the Pentium III, there's just no way around that. Intel has invested too much time and money into the optimization of applications for the Pentium 4 architecture and its execution core to throw it all away and revert to the old way of doing things.
That isn't to say that elements of the Pentium M design won't be included in Pentium 5 or whatever the next chip will be called. Even today's Pentium 4 already has a handful of key features borrowed from the Pentium M design. We saw examples of this with the launch of Prescott; the indirect branch predictor used in Prescott was originally introduced with the Pentium M processor. It would also be safe to say that a number of improvements that Intel is introducing in the next version of the Pentium M, the dual core Yonah, will eventually make their way into future Intel desktop CPUs as well.
But with a very high cost of ownership, thanks to high motherboard prices and correspondingly high CPU prices, not to mention a very limited upgrade path, the Pentium M just isn't suited for the desktop. And unless these deciding factors change significantly in the near future, it won't be for some time to come.
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CSMR - Monday, February 7, 2005 - link
The fact is it's an excellent processor for business use (speed, quietness, reliability) and multimedia use (quietness). Anandtech is full of gamers; but there is no denying that using a computer as a media centre is becoming a big thing, or that low-power, quiet operation is necessary. High motherboard prices are because the desktop PM motherboard market is very small. There was a comment in the review that the PM architecture doesn't scale well. I am sure that is so; but what processors do scale well? It's because they don't that everyone is about to go dual-core.bobsmith1492 - Monday, February 7, 2005 - link
Thanks #12 :PZebo - Monday, February 7, 2005 - link
I myself have been guilty of hyping dothan after seeing GAMEPCs "opimistic" review. This should quell that.:DZebo - Monday, February 7, 2005 - link
Anand best review I've read here, thanks a lot, nice to see you scribing again..:)Seems again, like the tech report review, with a comprehensive test suite such as this one dothan has some collosal performance flaws, and simply can't match up the A64 across board. It looses 30 out of 41 benches at same speed, some huge. 2.0 vs 2.0..
I posted in CPU forum how turion/lancaster will be 25W.. could this be the end of DOTHANS laptop dominace?
Brian23 - Monday, February 7, 2005 - link
I agree with #10.bobsmith1492 - Monday, February 7, 2005 - link
Sorry; first time commenting. I couldn't remember my login name before.Anyway, my laptop OCs better than that. Granted, it's a 1.7 to begin with, but the FSB will do 125 easily, with the same ram increase to boot - 420 MHz, with processor at 2.125. It will do a tad bit more, but that's enough for a laptop I'd say.
bobsmith1492 - Monday, February 7, 2005 - link
testKalessian - Monday, February 7, 2005 - link
#6, Oh yeah? Well, give a P4/A64 an SXGP(Super eXtremely Good Performance) setting and stay out of ITS way!Yawn, right now the P-M doesn't impress me at all. Let a CPU built for mobile systems stay in mobile systems until it gets rebuilt for desktops properly.
Great review, learned a ton :)
GnomeCop - Monday, February 7, 2005 - link
I have a 2.0ghz dothan system, I upgraded from an old 533mhz fsb p4.The speed for my work and games are just fine. I have a leadtek GF6800ultra in my system and its the only thing I have to worry about cooling.
CPU is passively cooled and the system is expremely quiet running on a 359watt psu. By the time I need to upgrade, I will be buying a whole new cpu/mobo/everything anyways.
ksherman - Monday, February 7, 2005 - link
seems like an a really good processor for buisness machines, given the L1 cahe speeds... and not much else (snas uber low power consumption)