Anandtech MBP 15" Battery Tests

Discussion in 'MacBook Pro' started by rawd, Apr 24, 2010.

  1. jmdMac macrumors regular

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    Feb 8, 2010
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    Alaska
    #2
  2. trevorplease macrumors regular

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    Feb 13, 2009
    #3
    "Note that your mileage may vary considerably here. Years ago Intel started shipping its processor families with a range of core voltage options. Two 2.66GHz Core i7s may run at wildly different core voltages, which would ultimately impact battery life. It’s possible that I got a particularly bad Core i7 (or particularly good Core i5) and that you’ll see a different gap than I did." - Anandtech

    I'm not sure I'm following, there are different kinds of i7's in the MBP line???
     
  3. mgacam2 macrumors regular

    mgacam2

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    Jul 27, 2007
    #4
    What they mean is that when a CPU is made they each need a slightly different voltage in order to maintain a stable speed. For instance a 2.4 ghz core 2 probably needs a 1.15 volt core to stay stable but if the speed ramps up aka the mhz to for instance 3 ghz the voltage has to change to keep stability. Generally when a CPU stays at the same speed they can usually keep the core voltage the same across the line as there is a bit of play space so to speak. The difference is it sounds like since all the i7s do the turbo boosting that they voltage also changes on the fly and thus there is alot more discrepencies with the changing speed. That means that the voltages may vary on the exact same cpu. They still are 35 watt cpus but its just that little bit difference in power to maintain the stability of the higher clock.
     
  4. trevorplease macrumors regular

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    Feb 13, 2009
    #5
    So when shopping for a macbook pro, these different voltages are significant in that different laptops will have very different battery life?
     
  5. SA22C macrumors regular

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    Top Gear Test Track.
    #6
    What Anand is saying is that it's a crapshoot. You could compare two otherwise identical 2.66 GHz processors and find that one runs at a higher voltage under load than the other. This is for stability reasons and due to the variable quality of production at the increasingly small fab processes that CPUs are made on. All of that said, I don't think that the variance is as pronounced as he is implying.
     
  6. trevorplease macrumors regular

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