Filed under: Portables, Macbook Pro, MacBook
MacBooks take performance nosedive on AC power alone
Here's a curious thing. Gearlog is reporting that in testing a MacBook Pro, they found substantially lower performance while running on AC power alone, with the battery removed. Apparently, Apple doesn't hide this quirk; there's a Support Document claiming that this is done to prevent "the computer from shutting down if it demands more power than the A/C adapter alone can provide."
On their new unibody MacBook Pro, Gearlog noted a 36% lower processor benchmark without the battery. The upshot is simple: leave the battery in, even if you use your MacBook (Pro) at your desk. Interestingly, at the same time Apple does recommend allowing the battery to discharge at least once per month.
[via Engadget]
![TUAW [Cafepress]](http://www.blogsmithmedia.com/www.tuaw.com/media/tuaw-cafepress-promo.png)
Reader Comments (Page 1 of 2)
Matt McN said 8:10AM on 11-23-2008
This has always been the case, but I'm not sure if it was this bad.
Reply
psj said 8:35AM on 11-23-2008
Intel based mac laptops have always done that, it's been widely known and you can see it happen with any cpu monitoring app. Once you remove the battery, the cpu steps down to the lowest p-state. If you don't want that to happen, use an app like coolbook to set your own speedstep rules. Gosh, what counts as "news" these days!
Reply
Krest said 9:10AM on 11-23-2008
exactly. keeps me wonder why every mac-blog bothers to write about that.
with battery: http://img.i7m.de/images/hp4at-sfde8-3vzt9-omdkp.png
w/o battery: http://img.i7m.de/images/awl3g-cfiyq-agykk-wzrg4.png
Level 5 said 11:28AM on 11-23-2008
I know the Mac guys might not be well versed on this having only 3 years of Intel machines, but ALL Intel machines are affected by this, not just Macs. Even my 12" P3/1Ghz from 2002 has this "feature". The problems in the new Macbook/Pros is more than likely compounded by the high power requirements of the video card. As Vandil said below, Intel CPU's and boards will step down based on heat and power abnomalities.
mungler said 9:16AM on 11-23-2008
AAAAAARRRRGHHH!!!
If I see this 'story' on *one more* mac site, i'm going to shoot someone.
ALL INTEL MAC PORTABLES DO THIS, THEY ALWAYS HAVE, GET OVER IT PEOPLE!
Reply
vandil said 9:59AM on 11-23-2008
Newsflash: Laptops working under non-optimal power conditions will step themselves down. Film at 11.
Reply
Ryan S. said 10:22AM on 11-23-2008
Question: Why would you take the battery out, if it stays fully charged when it's plugged in any way? O_o
Reply
basscadet said 10:37AM on 11-23-2008
I always take batteries out of laptops when I'm using them with AC power as the constant recharging wears them out faster than leaving them on the side and charging them up whenever you plan on using the laptop without AC. All the laptops I had over the years had longer battery life when battery was charged only when it was about to be used instead of being on the laptop all the time it was running on AC.
Big John said 11:42AM on 11-23-2008
Then enjoy the slow performance, basscadet!
Hawkman said 11:42AM on 11-23-2008
I have no idea. My thought upon first seeing this story was, "What kind of retard...?!" Yet, the story has got repeated everywhere. Either there are more retards around than I thought, or it's a slow weekend.
I understand laptops no longer attempt to charge the battery when full, so it seems pretty pointless to remove them. Dangerous, even, when you consider the possibility of a MagSafe adapter (which I love) getting knocked out.
Moral of the story: you want a desktop, buy a desktop. Don't buy a laptop and use it as a desktop, because, astoundingly, they're not perfectly suited to that. Who knew?!
"Interestingly, at the same time Apple does recommend allowing the battery to discharge at least once per month." - seeing as you can't discharge the battery if you disconnect it, I'm afraid I don't see your point. Yet another reason to keep the battery in, people.
umijin said 10:26AM on 11-23-2008
Hmmmm.... The description on the site doesn't exactly say switching to the Mac, but switching to VMWARE on the Mac.
So, it doesn't have to be Windoze you are switching from, as far a I can see.
You could be moving from Parallels or BootCamp, I suppose.
Reply
umijin said 10:28AM on 11-23-2008
This is such a non-issue, because virtually NO ONE runs their laptops without the battery when its plugged in. Get over yourselves!
Reply
Peter said 10:37AM on 11-23-2008
Folks,
You remove the battery to protect if from premature aging. It's commom knowledge about Li-Ion batteries; they age very fast when heated and fully charged, like when in a laptop running on AC. Read up, all you haters.
/Peter
Reply
Big John said 11:45AM on 11-23-2008
That's great, but does absolutely nothing for the impracticality of the situation. The number of people out there that remove their batteries when plugged into AC power is absolutely minute compared to those that don't even bother.
I've used my laptops this way for years and I've never seen a huge cliff drop-off like those that constantly fear monger seem to think exists.
eric f. said 12:01PM on 11-23-2008
Are you suggesting that a micro-niche of "laptop battery removers while on AC power" fanboys/haters now exists?
hans said 11:28PM on 11-23-2008
I have to agree with Big John. I used to remove my battery all the time when using my 1st generation Macbook Pro on my desk. The characteristics of Li-Ion, from what I understood back then were:
- Doesn't like hot places (inside the car, etc.)
- Should be charged as often / as many cycles as possible / should not be deep-drained
- Ideal long-term storage charge is at the 40% level
- Should not be left charging indefinitely
Keeping these in mind and adhering to what I thought were "good" battery maintenance practices, I have to say that over the course of the next year, that battery experienced one of the worst performance degradations I have every seen in my entire life. I don't know if I just received a bad battery or did something wrong somehow, but that battery was totally underused (ran maybe a total of 7 cycles only because it was almost never connected) and can now only last me a little more than an hour on a full charge, even when properly drained and recalibrated.
Then I came across a thread where people were talking about leaving the battery on or removing it. Some seemingly very tech-savvy guy mentioned that it doesn't really matter in the end, and that any perceived benefit to keeping the battery off may not even amount to anything significant.
Things being such, I've kept my early 2008's Macbook Pro battery on since day 1, and so far, I haven't seen noticed one bit of degradation in performance.
Tom said 10:41AM on 11-23-2008
And why are you so ignorant to believe that everybody knows this? I didn't know this, and I've asked several friends with a Mac, none of them knew this. So it's good that TUAW posted this!
Reply
James Donevan said 10:48AM on 11-23-2008
Peter says:
"You remove the battery to protect if from premature aging. It's commom knowledge about Li-Ion batteries; they age very fast when heated and fully charged, like when in a laptop running on AC. Read up, all you haters"
Looks like reading might be helpful if you regularly do this (ie run with the battery removed). Apple is very clear:
"Important: It is strongly recommended that you do not use your MacBook or MacBook Pro while the battery is removed."
Reply
Jesse said 11:09AM on 11-23-2008
Is there a conspiracy between battery manufactures and laptop makers to get us to wear-out our batteries quicker? Michael Moore film at 11.
Reply
mrsteveman1 said 11:12AM on 11-23-2008
"claiming that this is done to prevent "the computer from shutting down if it demands more power than the A/C adapter alone can provide."
So that means there are situations where it would in fact be draining the battery even while plugged in, otherwise the A/C would be (and should be) sufficient. That means such a performance state is unsustainable no matter what you do, plugged in or not. That's very odd.
Reply