I've had my Compaq laptop for about 3 years, and the original battery has only decreased in capacity maybe 7%. I can attribute that to removing the battery and using it only so often, while enjoying full processing power plugged into AC. If used in conjunction with a good UPS, there is no reason to have this type of scaling back design. If it's because of the AC adapter's 85 watt output, they should have made a better one, it's not as if Apple makes products geared for the thrifty consumers.

So what I'm reading into this is users who happen to have a 2-3 year old battery and don't want to replace it will receive a performance penalty? That's utter crap!

A laptop AC adapter must provide more than enough power to run (and here's the important part) *and* charge the battery simultaneously. This always leaves enough headroom to ensure there's enough power.

I reject Apple's notion that a MacBook Pro without a battery will draw more power than the AC adapter it shipped with.

In some *strange* case where a user has a 3rd party AC adapter, this might be helpful; and if a Mac user called Apple to complain about it, the first thing Apple Tech Support will say is "Do you have an Apple-supplied AC Adapter?" "No?" "We cannot support your configuration, let me direct you to sales so you can buy an apple-certified part."

Any questions?

battery discharge can be confirmed by Apple's own user guide found here: http://www.apple.com/batteries/notebooks.html

I wonder if the same holds true if the macbook is running vista/xp/Linux???? whether it is a software switch or built into the hardware?

For god sake! Who the hell believe that Apple only wants to prevent the computer from shutdown when not having the battery? It's a clear way to force deprecation on old notebooks as their batteries become inoperable faster. And I read about this "policy" one year and half ago. I just can't believe that Apple can't do a powerful enough adapter but prefers that the commercial clockwork keeps going.

So if the power adapter can not run the notebook on its own, how the hell does it change it? Does encoding a video on it have to draw into the batter eventually killing it? Something is not right.

The macbooks should not even need that much power.

Keep in mind that li-ion batteries are not the same as the older nickel-based batteries.

I think it was a legitimate concern when building and programming the laptop, but I think the editor could have possibly made a better title, I read this because I looked at the title and though "Really does it now?"

The CPU power is cut because the AC adaptor can't support it? The CPU needs both AC AND battery power to fully work? There is either super incompetence here or some kind of ridiculous battery scam going on, as suggested by another post. This is the most assinine thing I've ever heard!

Yeah something is up, an adapter should be able to provide more than sufficient power to keep ure laptop going at full load AND charge ure battery at the same time, if not, then while ure using your macbook for whatever purpose, the battery would only be charged intermittently while attached to the laptop and hence significantly increasing charging times.

I'm guessing apple decided to make a lower powered adapter in order to increase profits while cheating the consumer. Its a shame, dell, toshiba, Hp and the rest making good adpators that charge ure laptop's battery while plugged in and do it pretty darn quickly (even if ure using your pc at the time).

They (however) do get very hot in the process so i'm guessing the components used in them are cheap as well. Either way, i'd rather have a laptop running at full power with or without the battery rather than castrated performance cause the battery was missing when i decided to use my laptop. Crazy stuff!

'i-savings' HAHAA they - like in late 90's Toshiba - used battery as buffor. If battery isn't fully charged (or its dead) some Toshiba notebooks was unable to turn on on power supply. ...savings , savings ...

i agree with all people here. we know that an AC adapter should be more than capable of charging and operating a notebook at the same time.
also on the part, we know that a complete discharge will destroy a lithium ion battery faster, i think its also the same with NiMH.
the only advantage of a complete discharge is avoidance of memory effect which is not present in lithium ion batteries.

i could have believed one comment here that it forces depreciation faster but i DON'T think an old battery will force the macbook slower.
one thing good though with having a battery always on the notebook is avoiding loss of data during power failures.

I find it really hard to believe the conspiracy theorists who think Apple is doing this to force decreased battery life upon the masses as a method of selling more replacement hardware. I mean, their logic makes sense, and frankly I'd prefer using Apple's compact 85W adapter with this type of functionality to them pushing a larger, bulkier adapter for those rare times that the entire system is running at full capacity. Adapter efficiency under extreme heat also factors in...

The point of this article is not that Apple notebooks are constantly sucking on the battery even when plugged in. It is that occasionally when your 2.8Ghz processor, 15" screen (brightness cranked), 9600 GT, and 7200RPM HDD (the Macbook Pro's top configuration) are all running at max capacity, you may need to use a bit of the batteries power, and Apple has taken steps to ensure your system doesn't shut down. What other notebook fits that kind of capacity into an 85W envelope anyway? Most others, comparably configured, would ship with a bulky-as-hell 120W which, believe you me, is not something you want to travel with, a fact which entirely eliminates the advantage of the Macbook Pro's design.

Yes, Apple could have designed the functionality better. Spikes in power demand are certainly hard to detect in time to prevent a shutdown, but not so hard that this functionality should be turned on all the time, regardless of load. However...

While a lot of you may not like Apple, that shouldn't spur you to stretch every bit of negative press into a conspiracy based on ignorance.

Simulated conversation that I would have with myself if I had an Apple Macbook.

"Hey sweet I gonna play (insert 3D game here)."

"Oh damn I left my Macbook in standby and only have 25% battery. I guess that means I can only play (3D game) for 30 minutes or so before my battery runs out and my Macbook goes into cripple mode."

"Guess I shouldn't have gotten that 9600 GT, or maybe that 2.8 Ghz processor, or it could be that 7200 RPM hard drive draining my battery."

"Actually I guess I shouldn't have bought a Macbook, because it is incapable of sustained full load use and charging itself.

I can understand Apple's using the battery as buffer,however if you're running a processor intensive task (EG: Video encoding,or frame rendering) the battery will lose it's charge.

On normal conditions this should not be an issue, since most programs only require a small cpu or GPU loadtime,and the majority of the time the processor is running at low speed,saving power which can be directed to charging the battery.

Apple's computers aren't really made for gaming anyways, but that they advise to run a Li-ion battery totally empty I find weird.

It is so, that a Li-ion battery can be destroyed (can never reach the voltage needed to start charging) when being completely empty.

this is because apple's ac adapters are garbage.

why do people continue to buy this overpriced junk??

It is a marketing scam that apple has going on. Make the batteries die faster rather you use them or not that way users are forced to buy more batteries

the adapter gives enough power

my friend has a mac book pro and when running a 3d modeler, he left the PC rendering for over a week

if the adapter didn't give enough power, then the battery would have dies within hours

i really wish they would add a edit feature to comments

the system also never clocked down (well he didn't notice any change in clock speed)

his mac book pro is about 2 years old his battery still works fine don't think he ever leaves the dorm with it(i wouldn't either something that overpriced is bound to be stolen if it is taken out in public) so it is always plugged in )

That said, Apple should not clock down without a battery then since your friends power supply can clearly run the full system non stop. Who knows why they do that.

You should be able to goto tomshardware.com and click forums login and edit posts in the actual forums