Introduction

Dothan is something that both perplexes and intrigues us at the same time. Not quite a Pentium 3, not quite a Pentium 4, and not quite something that is entirely different either. Meanwhile, the NetBurst architecture has come under serious strain over the last few years, particularly since Intel's Prescott launch. Is Intel still capable of killer products? And more importantly, do they still dominate on Linux?

As many who follow our Windows reviews know, Pentium M on the desktop is something a few years in the making. Even when the original 130nm Banias processor showed up in 2003, reviewers and customers alike were astonished with the technology. Intel received even more praise when their 90nm Dothan chips of the same product line showed up - utilizing less than 30W during peak operation and less than 5W on idle. Most of these advancements were due to Intel's controversial strategy to rethink the P6 architecture and refining a particularly interesting technology called Enhanced Speed Step. Enhanced Speed Step, also known as EIST, gives the operating system the ability to dynamically clock the processor. Typically, Windows will dedicate the full 100% of the Dothan's clock during intensive operation, but throttle the processor as far down as 10% of its capable speed when the computer is just idling. Thus, Pentium M has achieved incredible status among overclockers and HTPC enthusiasts - on Windows. Today, we will briefly explore the versatility of Pentium M on the Linux desktop. Lessons learned should also apply to the notebook market as well.

That being said, there are already a few fundamental flaws with the Pentium M architecture on Linux, the largest of these being compiler optimizations. While Opteron/Athlon 64 and Pentium M share substantial optimizations from every corner of the OSS universe, Pentium M receives very little regular attention. Dothan/Banias are slightly cursed, since most Linux OSes are built on the - mtune=i686 flag, which specifically tunes compilation to the P6 core (Pentium Pro), from which the Pentium M is derived. Why is that a curse and not a blessing? Although Dothan and Banias certainly share some key elements with the P6 architecture, they are far from it. Pentium M's Micro Ops Fusion, local branch prediction and general optimizations across integer division and register access are completely ignored by the compiler, even when setting - march=pentium-m, since most compilers (particularly anything before GCC 3.4.2) tend to just categorize Pentium M as a P6 processor with a higher clock.

Of course, the Intel C compiler, ICC, behaves very differently, but unfortunately, isn't very free either. We have a few tests today that include the non-commercial ICC as well and we see how they stack up against GCC 3.4.1. So, if it doesn't bother you that the majority of Linux sees your new Pentium M as a glorified Pentium Pro, without further ado, let's check out how it actually performs against other processors that we have looked at in the past.

The Test
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  • KristopherKubicki - Friday, December 24, 2004 - link

    phaxmohdem: these were just linux tests, but i do believe we have all of those render benchmarks coming up in the Windows analysis.

    Kristopher
    Reply
  • overclockingoodness - Friday, December 24, 2004 - link

    #44: The results could be better on the Windows platform, as stated in the conclusion. Reply
  • sprockkets - Friday, December 24, 2004 - link

    If you want to see the clock speed dynamically adjusted just roll your mouse over the kpowersave daemon running in the tray (at least it works for me under SuSE 9.2). Even my little Via C3 800mhz system will scale from 399 to 800mhz depending on load. It may even work in 9.1 (the part I couldn't enable was the suspend options). Hell, SuSE even can make my Hitachi Desktar drive go quiet to performance mode right in the OS! Reply
  • formulav8 - Friday, December 24, 2004 - link

    As this article shows, alot of people way overhyped this chip. Yes its not bad, but not the P4 Killer that alot of people claimed.

    It is interesting but it doesn't look like Intel will make a Desktop chip based on this cpu yet in the near future. Dual cores would be very interesting though.

    JAson

    Reply
  • phaxmohdem - Friday, December 24, 2004 - link

    This chip seems to be a god-send for the corporate IT directors needing machines for their monkeys to do Word and Excel documents on. As for me though, I don't think I could purchase a chip that has as spuratic performance levels as this. I do so many different things on my box, especially in content creation, that I much prefer the consistant performance of my current Athlon64 proc. across all applications.

    Just a suggestion, I would love to see some Adobe benchmarks on these chips... After Effects render times, Premeire Render times, Photoshop performance, etc as these are all applications I use nearly daily. Thanks.
    Reply
  • HardwareD00d - Friday, December 24, 2004 - link

    When someone does a full set of benchmarks of the Pentium M for all categories across the board vs A64 and P4, then I'll seriously consider if this chip is worth its salt. Until then, I am unconvinced that it is anything special. If it is so good, then why hasn't Intel made any attempt to push it as a desktop chip? Reply
  • segagenesis - Friday, December 24, 2004 - link

    It was looking pretty good until you mentioned the price :( Ouch. Reply
  • Ozenmacher - Friday, December 24, 2004 - link

    And go Vikings! Reply
  • Ozenmacher - Friday, December 24, 2004 - link

    Merry Christmas to you too! Reply
  • skunkbuster - Friday, December 24, 2004 - link

    merry christmas!

    Reply

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