Model A1286. Released February 2011 / 2.0, 2.2, or 2.3 GHz Quad-core Intel Core i7 Processor

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Why does MBP run slower with cheap battery?

What is it that causes my MacBook Pro (A1286) Early 2011 to run slower with some (read cheaper) batteries?

  • Is there hardware inside the battery case that causes it?
  • Is there a way to fix the reduction in processing speed?

What if I replaced just the battery cells and kept all other parts of the original battery pack?

Here is the coconutbattery screenshot.

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I doubt your system is running slower due to a cheap battery. I could see the wrong battery being an issue or one that was bad (this is were a few cells are not working).

So lets dig a bit deeper into your problem to see if we can isolate the cause. First I would download this gem of an app: CoconutBattery paste a screenshot of the main window into your question here so we can see what it's telling us. Here's how: Adding images to an existing question

In the mean time did you calibrate your battery? This is a very important step when replacing a battery. Here's the steps: NewerTech - How to Calibrate a Mac Laptop's Power System

A common issue with this series is the HD cable can get worn and this can make the system appear to be running slower! Here's the IFIXIT guide to replace it: MacBook Pro 15" Unibody Early 2011 Hard Drive/IR Sensor Cable Replacement and you want to use the newer version of the cable: MacBook Pro 15" Unibody (Mid 2012) Hard Drive Cable. The area which wears the cable is on the rough surface of the uppercase. I place some electrical tape on the case where the cable rests.

Lastly, Hard Drives do need a bit of TLC! Over time the files get fragmented! Which slows their access as well as the systems ability to use virtual RAM space within the drive. I do recommend you yearly defragment your HDD. SSD are very different devices and don't need this. In any case I would first make a good backup of your drive with TimeMachine to an external drive before doing this.

MacBook Pro 15" Unibody (Mid 2012) Hard Drive Cable Image
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Adding images to an existing question

Difficulty: Easy2 - 5 minutes

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Is there a way to test the cable without replacing it?


Sorry not really. I replace them every time I replace a drive or take it out.


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