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The reason, at least in my experience, is a lot less conspiratorial than that. Most modern MacBook Pros actually have the ability to ramp up the CPU's draw whe

by dljsjr 13y ago

The reason, at least in my experience, is a lot less conspiratorial than that. Most modern MacBook Pros actually have the ability to ramp up the CPU's draw when on AC power so high that even when plugged in, they will cause battery drain. By allowing MacBooks to run with no battery in them, it would be possible to cause the machine to shut down. I have been told that this is a feature, not a design flaw. Some have told me that it's simply required for burst processing. Others have told me that it's related to battery health; it's bad for LiIon batteries to remain fully charged without discharging on occasion. I have no idea what the real reason is. I do know that current rMBPs have issues with throttling based on thermals, but this has nothing to do with battery life.

corin_ 13y ago
Surely the CPU at 55% wouldn't draw more power than it can draw from AC? If that was the cause couldn't they just cut off the very top end of CPU usage?
onebaddude 13y ago
>MacBook Pros actually have the ability to ramp up the CPU's draw when on AC power so high that even when plugged in, they will cause battery drain So why not limit the CPU to: (Speed at which batter drains) - 1%?
iSnow 13y ago
> Most modern MacBook Pros actually have the ability to ramp up the CPU's draw when on AC power so high that even when plugged in, they will cause battery drain Sounds like a major design flaw. Imagine you want to go on a flight and do something really CPU & GPU intensive and afterwards discover you have drained your battery. Apple should buy beefier power supplies if this is the cause of the problem - probably they are trying to shave 3% off the unit price by ordering whimpy power plugs.
- nwh 13y ago
  Major? It's been that way since 2007 at least, it's just a side effect of the way they design their machines. It's not as if this is a recent thing that Apple has just introduced.
- mbell 13y ago
  > Apple should buy beefier power supplies if this is the cause of the problem - probably they are trying to shave 3% off the unit price by ordering whimpy power plugs. Apple has not historically been one to skimp on power supply costs, to the contrary the supplies they provide are some of the highest quality I've seen in terms of build quality and part selection. The actual problem is more one of form factor. Apple has a certain expectation for size/weight/usability of their laptop supplies and meeting those goals with a 150W supply just isn't realistic.
- dljsjr 13y ago
  This hi-draw mode is actually only available when on AC power. Doing anything CPU and GPU intensive will obviously increase battery draw, but these exceptionally high CPU speeds are only possible when the MagSafe connection is active.
nwh 13y ago
This is completely correct. At full load I can draw 100W+ from my MacBook, which does indeed drain the battery. It's just a side effect of them having a small lightweight charger, and it's never affected me in the slightest. This is just some wild fantasy dreamed up by the original articles author.
mbell 13y ago
To use an example: the RMBP comes with an 85W power supply but it's CPU has a TDP rating of 47W and GPU a rating of 45W for a total of 92W. Without even getting to powering other circuitry, the display, or including conversion efficiency, it's pretty obvious that it can't run full bore off the wall supply alone.

by dljsjr 13y ago

corin_ 13y ago

Surely the CPU at 55% wouldn't draw more power than it can draw from AC? If that was the cause couldn't they just cut off the very top end of CPU usage?

onebaddude 13y ago

>MacBook Pros actually have the ability to ramp up the CPU's draw when on AC power so high that even when plugged in, they will cause battery drain So why not limit the CPU to: (Speed at which batter drains) - 1%?

iSnow 13y ago

> Most modern MacBook Pros actually have the ability to ramp up the CPU's draw when on AC power so high that even when plugged in, they will cause battery drain Sounds like a major design flaw. Imagine you want to go on a flight and do something really CPU & GPU intensive and afterwards discover you have drained your battery. Apple should buy beefier power supplies if this is the cause of the problem - probably they are trying to shave 3% off the unit price by ordering whimpy power plugs.

nwh 13y ago
Major? It's been that way since 2007 at least, it's just a side effect of the way they design their machines. It's not as if this is a recent thing that Apple has just introduced.
mbell 13y ago
> Apple should buy beefier power supplies if this is the cause of the problem - probably they are trying to shave 3% off the unit price by ordering whimpy power plugs. Apple has not historically been one to skimp on power supply costs, to the contrary the supplies they provide are some of the highest quality I've seen in terms of build quality and part selection. The actual problem is more one of form factor. Apple has a certain expectation for size/weight/usability of their laptop supplies and meeting those goals with a 150W supply just isn't realistic.
dljsjr 13y ago
This hi-draw mode is actually only available when on AC power. Doing anything CPU and GPU intensive will obviously increase battery draw, but these exceptionally high CPU speeds are only possible when the MagSafe connection is active.

nwh 13y ago

This is completely correct. At full load I can draw 100W+ from my MacBook, which does indeed drain the battery. It's just a side effect of them having a small lightweight charger, and it's never affected me in the slightest. This is just some wild fantasy dreamed up by the original articles author.

mbell 13y ago

To use an example: the RMBP comes with an 85W power supply but it's CPU has a TDP rating of 47W and GPU a rating of 45W for a total of 92W. Without even getting to powering other circuitry, the display, or including conversion efficiency, it's pretty obvious that it can't run full bore off the wall supply alone.