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
Understanding Pentium M Architecture
There is no doubt that the Pentium M performs very well as a low power, high performance mobile processor. We published two articles comparing the performance of the Pentium M Athlon 64 and Pentium 4, and in both cases the Pentium M did exceptionally well.The problem is that until recently, the only mobile platforms were all single channel DDR solutions, making it difficult to extrapolate how the Pentium M would fare against its competition in the desktop world. The desktop Pentium 4 and Athlon 64s aren't equipped with a single channel memory controller and they come in larger cache, higher performance models than in the thin and light systems on the mobile side that you find them.
Before we get to the actual performance comparison, there's a lot that needs to be understood about the Pentium M architecture.
While the underlying architecture of the Pentium M is far more complex than this, the real world application performance of the CPU can be summarized and understood when looking at four points:
- High IPC Core
- Low Latency L2 Cache
- Memory Latency and Bandwidth, and
- FPU Performance
Through the use of technologies like micro-ops fusion and its sophisticated branch prediction unit, the Pentium M ends up being even more efficient per clock than a Pentium III - despite having a longer pipeline. Based on its SPEC CPU2000 scores, the Pentium M features a 20% higher IPC than the Pentium III at an identical clock speed, despite its longer pipeline. The Pentium M vs. Pentium III comparison is similar to the Prescott vs. Northwood comparison, where the deeper pipelined Prescott was still able to make up for the loss in IPC through increases in efficiency and new branch prediction algorithms.
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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.