The engineers responsible for Intel's Core Duo processor and Centrino Duo platform are a bit frustrated.  Years of hard work leading up to the platform's launch in early January was first plagued by the problem of availability.  Core Duo and Centrino Duo notebooks are still not widely available, and that will continue to be the case at least for another week or two.  Outside of availability, another even more troubling problem crept up - could it be that the Core Duo platform had a bug that significantly reduced battery life when paired with any USB 2.0 device?  The folks at Tom's Hardware originally uncovered the issue, when they noted that battery life on their ASUS Core Duo notebook dropped dramatically after merely connecting an external USB 2.0 device. 

How much more frustrating could things get?  After spending years of work on a new mobile CPU and platform, your customers still really can't buy them and the one thing that everyone remembers about them is that they have some sort of a bug that reduces battery life.  When you've spent a good deal of your design time trying to increase battery life, having a reputation of decreasing it before notebooks are widely available has to be a tough pill to swallow. 

However, the case isn't as open and shut as that; the original test data indicated that this was primarily a Core Duo problem, while Microsoft insists that the problem should affect all notebooks.  The other issue is that, until last week, every single Core Duo platform that we could get our hands on was pre-production.  There's also the question of whether or not the problem is caused by the actual USB device used.  And finally, amongst all of this debate and finger pointing, a temporary solution actually existed, just begging to be tested. 

We set out on investigating this issue immediately after it was discovered, but soon found out that it was a lot more complicated than we thought upon first glance.  We've spent almost the past two weeks performing non-stop battery life testing on five notebooks with up to 4 different USB devices, testing theories, trying to pinpoint exactly what causes this problem and testing Microsoft's fix.  What follows is the process that we went through in our labs when faced with this strange bug.

Starting at the Beginning
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  • lazybum131 - Tuesday, February 14, 2006 - link

    Actually, if you take into account the larger capacity battery on the T60, 56WHr compared 51 WHr, the T43 comes out ahead most of the time. The T60 has a 9.8% larger capacity battery, but with the fix it only comes out ahead 3.2%, 1.85%, 8.24% and 5.04%.
  • Anand Lal Shimpi - Monday, February 13, 2006 - link

    I'm looking into this issue myself and I will have an updated Core Duo performance article in the coming weeks that will address this as well as many other items. I wouldn't use the ASUS notebooks to compare Napa to Sonoma, especially given the internal USB 2.0 camera. I am hoping to do a Lenovo based Napa vs. Sonoma comparison that will hopefully make things a lot clearer.

    Take care,
  • JarredWalton - Monday, February 13, 2006 - link

    I think that Napa allows a lower power setting, but you have to remember that two cores are still going to use more power than a single core when active. It might be interesting to see a test comparing Sonoma and Napa with the same CPU, as Dothan and Yonah both fix socket 479. There's also a question of the other peripherals, though: NIC, sound, screen, etc. all draw power. The newer Napa laptop from ASUS might have a better (re: brighter but more power hungry) LCD, for example, or a different HDD model. I don't know if they're strictly "identical" in other components, but a change of platform often involves other tweaks as well.
  • NullSubroutine - Monday, February 13, 2006 - link

    Id be more apt to say that the increase of the FSB and the second additional core are more likely the cause, because I think they did make sure the Asus laptops were exactly the same.
  • IntelUser2000 - Tuesday, February 14, 2006 - link


    Id be more apt to say that the increase of the FSB and the second additional core are more likely the cause, because I think they did make sure the Asus laptops were exactly the same.

    Keep in mind that with laptops especially with power consumption there is so many variations to battery life problem. It could be that the implementation of the BIOS or voltage regulator is different across the two. Voltage regulator is said to be 5-10% of total power consumption, so differences in V-reg can make differences you are seeing.

    Look here:">

    Even with a faster CPU, MSI M635 with 1.8GHz Turion outperforms HP Compaq nx6125 with 2.0GHz Turion. It also gets better battery life even with X700.

    I think 5% difference is well within the range.
  • huges84 - Monday, February 13, 2006 - link

    Doh! I completely forgot about the dual vs single core issue. And your other points are valid as well.
  • kmmatney - Monday, February 13, 2006 - link

    Looks like I'll be using my old USB 1.1 mouse when I travel from now on.
  • huges84 - Monday, February 13, 2006 - link

    Yeah, a lot of people will be checking what version of USB their mouses are. I know I will be.
  • Saist - Monday, February 13, 2006 - link

    In reguards to THG, I was surprised to see a link as well.

    In reguards to AMD systems, I have a Turion on hand from Fujitsu (Lifebook S2000) and have been unable to duplicate the power loss from a default state with either a USB 2.0 external DVD drive, or a USB 2.0 Plextore ConvertX device.

    I was also surprised to see that Anandtech didn't test any Turion systems themsevles in the article. But, having tested 2 Centrino systems of my own (one from Sager, the other from Dell), in addition to the Fujitsu, yes, it is time consuming.
  • Zebo - Monday, February 13, 2006 - link

    Anand refuses to test new turions similarly equiped.. don't know why I've emailed him never heard back. Go to laptop logic.

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