When my MacBook gets below 1% battery life I believe the CPU slows down. The battery indicator states I have 10 minutes left but those are the longest 10 minutes in the laptop cycle. Is there a way to slow down the CPU so I can get longer battery life at the cost of lower performance?
Well, Walnut wanted proof that the CPU was being throttled. So I went to sun spider performance test here ran the test at critical performance, critical performance while plugged in, calculating battery life, full power on battery and full power plugged in. Here are the results +/- 15ms on average:
Battery at full plugged in: 215.5ms Battery at full not plugged in: 203.5ms Battery at critical not plugged in: 555.0ms Battery at critical plugged in: 230.0ms Battery unknown not plugged in: 748.8ms
The results seem to indicate that OSX runs full CPU power when battery is full or it is plugged in. When the battery is in critical it runs half as fast (takes twice as long). When the battery status is unknown it runs one third as fast (takes three times as long).
To put it another way if the CPU is rated at 1Ghz then when battery is critical it's running at 500Mhz. When battery is unknown (and critical?) it runs at 250Mhz.
So I was right Walnut! TAKE THAT! IN YOUR FACE! ...I'm joking. You're alright. More people should ask for proof.