MacBook and MacBook Pro: Mac reduces processor speed when battery is removed while operating from an A/C adaptor - "If the battery is removed from a MacBook or MacBook Pro, the computer will automatically reduce the processor speed. This prevents the computer from shutting down if it demands more power than the A/C adaptor alone can provide."
Apple Notebooks Take Huge Performance Hit without Battery - "Apple's reason for forcing a drop in processor speed doesn't make a whole lot of sense."
MacBooks Run Slow Without Battery - "Gearlog's own results show a decrease of 36 percent in processor speeds without a battery attached on their unibody MacBook Pro. Our own tests show a decrease of 50 percent when rendering with one CPU, a decrease of 52 percent in multiprocessor rendering, while the GPU suffered a 40 percent decrease in performance."
"Fixing" kernel_task CPU Problems in MacOS 10.7/10.8 - Tweak IOPlatformPluginFamily.kext to disable throttling on faulty battery.
Disable OS X kernel_task throttling - Updated instructions for removing IOPlatformPluginFamily.kext.
/mac | Nov 15, 2018