Score:0

Battery-less MacBook Pro CPU is very slow

tr flag

I have an Early 2011 era 13" MacBook Pro with an Intel Core i7-2620M CPU and have made the switch to Ubuntu because my laptop's MacOS support was dropped a few years ago.

The battery has recently died and I have found a few new problems since this happened, the main issue being the notebook's CPU seems capped at 800MHz. I have tried various CPU-intensive applications, such as extracting a 7-zip file, to see if the CPU frequency increases as per /sys/.../cpufreq/scaling_cur_freq, but it remains set at 800MHz.

An Intel Core i7-2620M is rated to go up to 3.4GHz. I've heard that apple throttles CPU usage on MacBooks with weak or missing batteries, but I've also heard that this is limited to MacOS.

How can I get full performance from my system?

Hassan avatar
tr flag
OK, I also checked lscpu and at times I see the cpu works at 3400, but at the same time, scaling_cur_freq shows 800 and I don't see any real boosts in speed either. I used '7z b' in 'performance' and 'powersave' governors and got exact same results, even while lscpu was rarely reporting 3400MHz in performance mode.
David avatar
cn flag
Quite an old machine. What version of Ubuntu are you running?
Score:1
in flag

This is a hardware-specific issue with MacBooks that use the original MagSafe connector to charge.

When the battery is dead (or removed), the charger is unable to communicate with it. As a result, the charger supplies just enough power to have the main machine run and nothing more. The firmware inside the MacBook, recognising there is no functional battery, keeps the CPU bus rate down to its bare minimum, which is generally 800MHz for your model. This is true regardless of which operating system you choose to install on the machine.

The only viable solution is to replace the battery. This will reset the firmware and allow your CPU to scale up to its maximum viable rate.


Note: There are some ways you can force the CPU to run at 2.7GHz or 3.4GHz all the time with some special kernel commands, but you will not be able to use SpeedStep to automatically cycle up and down with the system load. It is not recommended that you do this unless you plan on adding the machine to the planet's e-waste in the very near future.

Hassan avatar
tr flag
What are such kernel commands? I might be able to setup my own speedstep scripts!!
in flag
Apologies, but I cannot in good conscience share manual over-clocking commands. Too many people have been *incredibly angry* on forums over the years because they followed the instructions, tweaked the numbers too high, thoroughly destroyed their systems, then cursed *my name* because of their foolishness. One thing I can say is this: If a person thinks they know better than a processor, they're usually wrong. Save yourself the stress, spend the $40 on a knock-off battery, and let the system regulate itself
Hassan avatar
tr flag
OK, Thanks. Unfortunately I live somewhere with no access to any kinds of battery replacements. I will try to find a way to do the job myself, but I see your points too. The laptop is already dead for me, even after destroying it, I won't loose much!
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