Intel's 90nm Pentium M 755: Dothan Investigated
by Anand Lal Shimpi on July 21, 2004 12:05 AM EST- Posted in
- CPUs
Final Words
Banias was revolutionary; it changed the shape of the mobile CPU world and it changed how we perceive mobile chip design to be pursued. It would be nice if the same mobile-oriented design methodology spread to companies like ATI and NVIDIA. Maybe then we would truly be able to game while on the go.Dothan, as an update to Banias, leverages Intel's 90nm process and some architecture tweaks to not stun us, but to keep us happy with the Pentium M platform. At 2.0GHz, the Pentium M 755 is easily the best chip that money can buy for a notebook. Clock for clock, it's faster and uses less power than Banias - there's really no reason not to like it.
If you're using your notebook for office applications and even for content creation applications, there's no beating the new Pentium M. Even developers will find short compile times, competitive with that of a similarly clocked Athlon 64, possible with the Pentium M at lower power usage as well.
What the Pentium M isn't, however, is as strong of a media encoding or workstation processor as either the Athlon 64 or Pentium 4. Partially constrained by its 400MHz FSB and single channel memory interface, the Pentium M is not the successor to the Pentium 4 that many will make it out to be. In many ways, the Pentium M is much like Intel's version of the Athlon 64, sans memory controller. The short pipelined design and accurate branch predictor give the Pentium M a nice and high IPC, similar to the Athlon 64, which give it strength in areas like business applications and are also responsible for its high performance in our compile tests.
With Intel's vision for the future being centered on media encoding and content creation, the Pentium M is the last thing that Intel would want to build their future desktop CPUs around. That being said, the Pentium M is quite possibly the best solution that Intel has for the office PC. It would be nice if Intel used the Pentium M as the basis for its desktop Celeron processor, instead of just a castrated Pentium 4.
The Pentium M will continue to be an excellent mobile chip, and the next incarnation of the Pentium M should be yet another revolution as it may even receive multiple cores as a part of Intel's overall threading strategy.
On the desktop, we may see features like micro ops fusion and some of the Pentium M's power saving technologies make their way into the Pentium 4's eventual successor. Dropping Prescott and moving towards Dothan would be a step back, using each architecture for their strengths and borrowing technologies for use in another would make much more sense for the future of Intel's microprocessors.
In the more short term, we may see some motherboard manufacturers make Pentium M based motherboards for desktop usage. Shuttle, in particular, is currently working on a small form factor box based on the Pentium M. That should be out by the end of this year.
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phtbddh - Wednesday, July 21, 2004 - link
What is the battery life of a Dothan compared to a Banias? I know the Dothan is suppose to be better, but can we see some numbers?tfranzese - Wednesday, July 21, 2004 - link
Not quite SKiller, a large part of the P4's dominance in media encoding is the high core frequency attributed to such a long pipeline.SKiller - Wednesday, July 21, 2004 - link
I think the assertion that.."With Intel's vision for the future being centered on media encoding and content creation, the Pentium M is the last thing that Intel would want to build their future desktop CPUs around."
..may not be correct as by your own admission:
"Partially constrained by its 400MHz FSB and single channel memory interface, the Pentium M is not the successor to the Pentium 4 that many will make it out to be."
So all Intel would have to do is up the FSB on a desktop version to improve media encoding and content creation performance and be competitive with P4.
mkruer - Wednesday, July 21, 2004 - link
you know i wonder just how much of the preformance is gained from the 2MB of L2 cache. If I recall from Aceshardware the 2MB is the sweetspot For mico op code, any more, and there is a preformance hit in either direction, Also on a side note. The 90nm Athlon 64 show a ~5% improvement across the board.dvinnen - Wednesday, July 21, 2004 - link
Yea, I was wondering the same thing. Why not just use a mobile A64 system with a mobile 9600. Acer and emachines make systems with them.alexruiz - Wednesday, July 21, 2004 - link
Another one: Was that difficult to get an eMachines M68xx for the review? Mobile against mobile.alexruiz - Wednesday, July 21, 2004 - link
Anand made a huge mistake in the Athlon 64 CPU selection. The mobile [b]A64 3000+ is clocked at 1.8 GHz with a 1MB L2 cache[/b]. He used a desktop 2.0 GHz with 512 K. This will affect the outcome, specially because clock speed matters more cache.I knew Dotham was going to give a very good fight, but I didn't expect it to win any gaming application ot Business Winstone. As reference, my M6805 A64 3000+ scores 22.2 and 27.8 in the BW and CCMW tests (7K60 hard drive, so not the same setup)
A very good review, but we can do better. I still want to see video encoding tests run with a commercial application, preferably 3 (Ulead Video Studio 8, Roxio Videowave 7, Pinnacle 9) and 2 alternative programs for DivX encoding (DVD2AVI and virtualdubmod are suggested. We have seen enough XMPEG from other sites)
Run some photoedition benchmarks not only with Adobe, but also with Corel Photopaint 11 or Roxio Photosuite.
AutoCAD is also expected to give an idea of what be attained. SolidWorks or UG would be fantastic, but those 2 are more of a wish.
How about more scientific or technical programs? Electrical simulators (PSpice for example), FEA (Nastran), MathCAd, Maple, etc.
More games were expected to be run. Howe about chess programs? How about OSmark, the succesor of COSBI by Van Smith?
I stressed the use of 2 or more applications that do the same to highlight the fact that software optimization matters a lot and that some myth about a CPU being "the best for that activity" are only myths.
All in all, Dotham is a potent rival that uncovers some weaknesses in the K7/K8 architecture that were noticeable against the P6 (Pentium II/III) but forgotten against the P7 (Pentium 4): [b]L2 cache performance[/b] and integer performance.
Regarding battery life keep in mind that the CPU is not the biggest spender in a laptop, the screen is. The K8T800, the most popular chipset for AMF64 laptops is a desktop part, and is quite voracious. Keep those factor when battery life is evaluated.
I foresee that SOI will give AMD the edge in battery life once they implement power saving caches, the biggest energy conservation feature in the P-M.
Comments are welcome
Alex
dacaw - Wednesday, July 21, 2004 - link
Well Dothan looks very much like a copy of a 32-bit AthlonXP to me.Comparing it to an Athlon64 makes no sense. Dothan is not 64-bit.
I bought an AthlonXP Barton mobile 2600 for $99 and it runs barely warm under PowerNow. What could you buy for the price of a Dothan? Maybe 5 top-of-the-line Athlon XPs?
Let's compare apples to apples and have a review of top-of-the line Dothan to top-of-the-line AthlonXP.
Oh, and drop those fake synthetic benchmarks. What point are they if they simply "favor" Intel processors (your comment in the review).
Come on Anand, lets have a review that really means something. Please!
Jeff7181 - Wednesday, July 21, 2004 - link
Can't wait to see battery life tests.mino - Wednesday, July 21, 2004 - link
Nice review, however it is a shame you didn't include Celeron 2.4 (which could be find in many SLOW notebooks) and also AXP-M 2600+ would be nice. -> this way it would be a complete notebook market review. - The best one.I'll love to see bench results of Cely and XP added (by using same desktop platform as you did in case of P4)
mino