A lot of laptops either refuse to run or heavily throttle while running without internal battery. I know pretty much all Mac portables do it. Basically the int

A lot of laptops either refuse to run or heavily throttle while running without internal battery. I know pretty much all Mac portables do it. Basically the internal battery is used as a buffer for power peaks. So the laptop can use more than the adaptor can provide for a short time. If it didn't throttle it would become unstable.