85w power supply enhance performace of unibody/aluminum macbook without battery

Discussion in 'MacBook' started by FriedPotatoes, Dec 1, 2008.

  1. FriedPotatoes macrumors newbie

    Joined:
    Nov 17, 2008
    #1
    Ok, I know the macbook comes with 60w power supply and I have read that 85w power supply is backward compatible with both MBP and MB. I have also read in a few places that it may charge the battery faster and the power supply to run cooler if using the 85w one. I have also noted that MB and MBP will run A LOT slower if one takes the battery out and run solely on power supply. Apple has quoted (and I don't really believe this) that the power supply does not have enough "juice" to keep the MB running at optimal performance if no battery is inserted. Since MB comes with 60w and this is not enough "juice", what if I use 85w power supply, and take the battery out? Theroetically, this should increase performace, right?

    Has anyone tried this and possibly have benchmark results?
     
  2. paolo- macrumors 6502a

    Joined:
    Aug 24, 2008
    #2
    I'm not sure about any of this, but this is what I understand from it.

    Euhm, the power supply is capable of powering the computer on it's own (after all, you can charge and use the computer at the same time).

    I'm pretty sure the computer knows if the battery is in place and it's purely software slowing down the CPUs. I think it's because the power supplies don't have surge protection of any kind and possibly offer a very fluctuating current. That's okay if there's a battery as it acts as a buffer to those kind of things. So apple probably put that in place in order to protect the computer if there isn't. If the power output is fluctuating and the computer is using a lot of power, it could be possible that it could starve the laptop, making it crash. That's what I understand from it all. So 85 watt or 60 watt should give you the best performance...
     
  3. StuBeck macrumors 6502

    Joined:
    May 6, 2008
    #3
    It doesn't charge any faster. The MB only takes 60watts, otherwise it would start to fry itself with the extra power its not designed for.
     
  4. silverblack macrumors 68020

    silverblack

    Joined:
    Nov 27, 2007
    #4
    I would put it this way. If the MB comes standard with a 60W ac block, then the MB is built to take less than 60W under any circumstances. So you are not going to see any advantange having an 85W ac block.
     
  5. alphaod macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    NYC
    #5
    The brick says 60W-85W which means it is autosensing will switch accordingly. The only downside is it's a tad bigger.
     
  6. No1451 macrumors 6502

    Joined:
    Oct 20, 2008
    Location:
    Ottawa, ON
    #6
    A loss in performance is not what you usually experience when you under power electronics.

    Best case scenario, the computer fails to boot entirely, worst case scenario, the hardware takes permanent damage.

    This might not be the case with laptops, but this argument makes absolutely no sense, by your logic, while my battery is charging my performance should tank, which, unless OS X has some really aggressive underclocking going on to save power, I don't believe to be the case. Take your logic on a side trip, lets assume that there ISN'T enough juice from the wall socket, and the battery does get tapped....well that makes no sense at all, cause to maintain the charge in the battery some of the juice from the socket would need to be tapped.

    Consider the logic of your statements and get back to us.
     
  7. silverblack macrumors 68020

    silverblack

    Joined:
    Nov 27, 2007
    #7

    According to this:
    1. Your MB can demand more power than the adapter alone can provide (and therefore tap into the battery's power).
    2. Your MB will reduce its processor speed when the machine detects that its relying solely on A/C ("there ISN'T enough juice from the wall socket" as you put it).

    The OP did not come up with this logic him/herself. It is widely posted in the internet, quoting sources originated from Apple.
     
  8. gnasher729 macrumors P6

    gnasher729

    Joined:
    Nov 25, 2005
    #8
    I recommend putting the battery back in the computer. Unless someone has stolen your battery, there is no good reason whatsoever to run a MacBook without its battery.
     
  9. No1451 macrumors 6502

    Joined:
    Oct 20, 2008
    Location:
    Ottawa, ON
    #9
    The thing that gets me is, if this is true, why does the battery meter not reflect this? Is it charging back instantly or just not adjusting itself so as not to alarm the user?

    Even if it is documented, it just seems far too stupid to be true. But then I guess that reality doesn't need to be plausible...

    Edit: Reading the link you posted, even they state that they have a hard time buying the logic behind this
     
  10. StuBeck macrumors 6502

    Joined:
    May 6, 2008
    #10
    Yes, I was referring to those who think the 85watt powersupply will charge faster. If it did, it would fry the system if it just blindly put in 85 watts.
     

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