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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bob661 - Tuesday, February 8, 2005 - link
The only problem with this chip is that the marketing is oriented towards the mobile market and therefore not a direct competitor to the A64. It would be nice if it was. It might bring some cats out of the bag on the AMD side. Competition in the marketplace is good for us all.jvrobert - Tuesday, February 8, 2005 - link
Really, AMDroids, get a grip. You're all excited because the AMD chips beat a mobile processor pretty handily, and because you are making some silly assumption that the Pentium-M in its current form is Intel's "last chance".First, Intel doesn't need a last chance. They make enough money to make AMD look like a Mexico City taco stand. So enough of those delusions of grandeur.
But on a technical front, if Intel ramps the clockspeed up to the 2.8 range (easy), and releases a desktop class chipset for the Pentium M it would match or exceed any current chip. And these are _basic_ steps. What if they made more improvements?
jvrobert - Tuesday, February 8, 2005 - link
bob661 - Tuesday, February 8, 2005 - link
#45You are a rock. The point of the article was to compare the P-M to desktop CPU's because most of us here wanted to know it will perform. And you know what? It performed very nicely.
classy - Tuesday, February 8, 2005 - link
I just can't help but to laugh at some folks. Its a nice chip but clearly not in the A64 ballpark. Its that simple. As far as the 2.8 oc, that was only accomplished in one reveiw. All the reviews show the same thing you have oc so it can it compete. What's interesting though is most of these Intel fanboys don't want to see a comparison of an oc'ed A64 vs a Dothan. Smoke city :)FrostAWOL - Tuesday, February 8, 2005 - link
IF the Pentium-M and P4 are electrically incompatible then someone please explain this:HP Blade system Pentium-M with Serverworks GC-SL chipset
http://h18000.www1.hp.com/products/servers/prolian...
FrostAWOL
jae63 - Tuesday, February 8, 2005 - link
Great review & of interest to those of us with HTPCs. Too bad the price point is so steep.One minor correction on page 11:
"The Pentium M does a bit better in the document creation tests, as they are mostly using applications that will fit within the CPU's cache. However, the introduction of a voice recognition program into the test stresses the Pentium M's floating point performance, which does hamper its abilities here."
Actually NaturallySpeaking uses almost no floating point but is very memory intensive. The performance hit that you are seeing is because it uses a lot of memory bandwidth and its dataset doesn't fit in the L2 cache.
Here's some support for my statement, by the main architect of NaturallySpeaking, Joel Gould:
http://tinyurl.com/6s4mh
segagenesis - Tuesday, February 8, 2005 - link
#43 - I think you have the right idea here. This processor is not meant to be performance busting but rather a low energy alternative to current heat factories present inside every P4 machine. I would love to have this in a HTPC machine myself but the cost is still too damn high. Hopefully higher production will bring the cost down.Aileur - Tuesday, February 8, 2005 - link
I guess the pentium M isnt ready (yet) for a full featured gaming machine, but with that kind of power, passively cooled, it would make for one hell of an htpc.PrinceGaz - Tuesday, February 8, 2005 - link
#45- It was not an unfair review, on the contrary it seemed very well done. The reason the P-M was compared with fast P4 and A64's is because they cost about the same.Maybe someone else buys your computers for you, but most of us here have to spend our own money on them so cost is the best way to decide what to compare it with.