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Celeron M vs Athlon XP M & Sempron M - power usage & battery life under low load

Discussion in 'Laptops' started by Nil Einne, Apr 9, 2005.

  1. Nil Einne

    Nil Einne Guest

    Hey all,

    Reading the title, you might be tempted to post without reading what
    I'm saying here, but please don't.

    I'm looking into this matter for a friend who wants a cheapish laptop
    for light usage. Obviously, performance isn't too important but things
    like price, weight, and battery life are. I have a good idea on advice
    based on my research but one thing I'm still not certain on is the
    battery life / power usage of the Celeron M vs Athlon XP & Sempron M.
    Originally, I thought the Celeron M would win no contest, I know the
    Pentium M will. But then when I looked into the Celeron M I quickly
    realised it wasn't just the reduced cache and clock speed, the Celeron
    M also lacked Enhanced Speedstep and "Deeper Sleep".

    Realising this, I've become a lot less certain. For those of you who
    don't understand, although the Celeron M still has a number of the
    power saving features of the Pentium M design, the lack of Enhanced
    Speestep is quite significiant. The 'deeper sleep' is also somewhat
    important I suspect as I understand it can result in up to 30% power
    savings over normal 'sleep'. As all (to my knowledge) mobile Athlon
    based processors have Power Now!, this means the AMD based laptops
    will be reducing their clock speed (and power usage) under low load
    whereas the Celeron M will always be at full speed (although obviously
    will be able to go into sleep states). I suspect under high load and
    if you force the AMD based systems to always operate at full speed,
    they will def lose to Celeron M systems, especially given that the
    Celeron M have a TDP of 21w whereas lower voltage AMD based systems
    tend to be 25w but this seems unlikely to be the case in low load
    systems. I suspect it's going to depend a lot on the load. If the
    Celeron M is able to enter sleep states a lot but clock speed cannot
    be reduced much for whatever reason, then the AMD based ones won't

    Therefore, I would like feedback, with regard to the power usage or
    battery life of a AMD based laptop (25w TDP or lower if that exists)
    to a Celeron M (not a ultra low voltage one tho). Preferbly from
    people who have tested this. Either via battery life of comparable
    batteries or if they actually tested the power usage under low load.
    Please do mention speeds, processor TDP if known, L2 cache size and
    also core type if known (for Celeron M either Banias or Dothan
    although I should be able to work out with other details). However,
    those who have compared Celeron M and Pentium M systems (with other
    comparable specs) under low load are also welcome as this should give
    some idea.

    Thanks all!!!

    P.S. If your a Intel/AMD fanboy and have nothing constructive to add,
    please don't bother to post.
    Nil Einne, Apr 9, 2005
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  2. Nil Einne

    Michael Lee Guest

    Are you looking for comparisons of the power consumption for each
    processor w/all other things being equal, or are you just looking for
    the best laptop for the money in terms of weight and battery life for
    your friend? If it's the latter, then you'll have to consider all the
    other things that require power such as the LCD screen, HD, video card,
    etc.. That would make also make comparing each CPU individually kinda
    pointless, since some laptops running a Celeron M might outlast one
    running a Pentium M depending on the other parts it has. The best thing
    to do would be to just look at all the estimated battery life for each
    individual laptop in reviews from PC World, Laptop Magazine, CNet, etc.
    Michael Lee, Apr 9, 2005
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  3. Hmmm, that's not so obvious, especially since the CPU isn't the
    biggest power drain.

    For what it's worth, at work I have a Dell X300 (Centrino, hence
    Pentium M) and at home an Averatec (mobile Athlon XP-M). The Dell
    gives me 2 hours on its standard battery and the Athlon 3 hours.
    Both are small laptops with 12-inch screens and both have similar-sized
    batteries. The Dell also has an optional extended-life battery
    that's good for 5 hours; the 5-hour battery sticks out the back
    and adds weight but it's a good compromise, I just used it on a
    trip. The Averatec doesn't have an extended battery; I suppose I
    could buy a second 3-hour battery and figure out a way to carry it
    safely on trips.

    Also, the Dell's 2-hour battery charges very fast. It's possible
    that the reduced capacity is a design trade-off to buy charge speed.

    Overall, it's pretty hard to say which laptop has the better
    battery life.

    I suppose that's bad, but in view of the above I recommend
    googling the web for reviews of Celeron M laptops if you want
    to know about battery life.
    Pierre Asselin, Apr 10, 2005
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