Can MacBook Pro's CPU slow down with bad battery?

Thanks for the tip man.

I have an MBP Retina mid-2012. It works very slow when is on the discrete video card which is more power hungry. I'll get the replacement in a few days. Hope it will fix it.

C

It's well known that Apple throttles the CPU (I heard halving the CPU clock) if a battery isn't detected. The 60W power adapter isn't enough if there's a surge in power needs, so reducing the clock is insurance against a random shutdown. Of course not having a working battery is a risk with the MagSafe adapter or any adapter if it's disconnected. I remember issues with tower computers sitting under a desk, if the power connector was bumped.

If the battery is bad or there's a break in the connection, then it should automatically throttle back.

Csound1 wrote:

It is possible if the battery is defective that the cpu will throttle down to a less power hungry speed. The only real way to tell is by fitting a new battery.

Battery information can be checked in System Report. If there's some sort of serious problem it should report it, although that should also show up on the battery indicator dropdown menu.

CoconutBattery might give an idea too. It does seem to be slow to respond to stuff like discharge rate. I pulled the power adapter and it took a while before it indicated that it was drawing more than 0 watts from the battery. When I reconnected it was still indicating that it was drawing from the battery. CoconutBattery also doesn't report how much power is drawn from the adapter.

Csound1 wrote:

I know that already, but thanks.

Cool. It sounds like you've got a bad battery. I've heard conflicting info on whether or not Apple will replace it for you given how old it is. I'm sure they have the OEM batteries though.

Battery diagnostics are kind of a strange thing. The developers can apply a model that basically estimates the remaining capacity based on monitoring the voltage/current and perhaps other conditions like temperature, and then storing data to a "scoreboard" within the battery. It's kind of weird because they have to adjust when the model doesn't line up with what the battery system is seeing. I had an issue with my 2007 (polycarbonate) MacBook battery. One day my wife was playing a game that turned the fan on full blast while it was off the adapter, and it just shut down. When I restarted the battery was reporting negative capacity. I kept that battery around for a while even though it said that it needed to be replaced. Eventually the status went back to "normal", then to "replace now", back to normal, etc. I was planning on getting a service replacement but the store I went to didn't have any. I finally got a service replacement after the battery started swelling. What I believe happened was during that crazy shutdown, something corrupted the status data in the battery and it could never really recover from that.

Early lithium rechargeable batteries were kind of an adventure because they didn't store battery status anywhere, and were basically just charged like you'd charge a NiCad or NiMH battery.

I remember a coworker who used to work at a big PC company making custom chips for them. But their head of battery research apparently would walk into the room where they were charging lithium batteries, and would quickly leave because he was worried that the room could go up in flames any time. I believe this was before batteries had onboard diagnostics to model the status. There was that big fire at the Sony plant in Japan that made the majority of lithium-ion batteries in the mid-90s, and that put a huge crimp on battery supplies for a while.

I can't really find much about how Apples stores data on their batteries, but Sony has some for their camera batteries.

http://docs.esupport.sony.com/dvimag/HDR-CX220_CX230_CX280_CX290_CX320_CX380_CX3 90_HDR-PJ220_PJ230_PJ320_PJ380_PJ390_gui…

y_p_w wrote:

Csound1 wrote:

I know that already, but thanks.

Cool. It sounds like you've got a bad battery.

It sounds to me as if you are very much mistaken in who you think you are addressing. Please review who you addressing replies to.

Csound1 wrote:

y_p_w wrote:

Csound1 wrote:

I know that already, but thanks.

Cool. It sounds like you've got a bad battery.

It sounds to me as if you are very much mistaken in who you think you are addressing. Please review who you addressing replies to.

My spiel was meant for the OP though, even though it was a response to your post for context. My mistake.

Zikkypikky wrote:

Thank you for you reply. However my battery does not act wierdly it just dies after some time – not high temperature or nothing. My point was only that my CPU probably reacts to the low power. I've already ordered new OEM battery so I will see and hope if it helps.

Sorry. I tend to be long winded. That was just a story about how the battery diagnostics can get corrupted. I'm thinking your battery may have status data that doesn't accurately match the state of the battery. I've seen stuff like that on my old iPhone 4s that was well over the number of cycles. The model used to estimate the capacity left can get less and less accurate over time. I'd see stuff like it reporting 25% capacity (and 100% reported was probably 40% of the original capacity) and then suddenly it would drop to 1% and then start a forced, but orderly shutdown.

When it just dies on you, are you getting a save to disk? Once you can restart it would look like how it was when it shut down, but kind of grayed out and then back to normal colors when fully recovered. If the power is just shutting off, then it's going to restart like a forced manual shutdown.

Did you check the number of cycles on your battery using System Report - under Power?

It is possible if the battery is defective that the cpu will throttle down to a less power hungry speed. The only real way to tell is by fitting a new battery.

I know that already, but thanks.

Good morning,

Unfortunately, I witnessed the same phenomenon as mentioned above on my MBP 13 E 2011.

After I changed my dying battery for a solid new one, overall performance seems to increase.

It doesn't just seem to, it actually does. It goes back to normal.