Does service battery warning cause Macbook to slow itself down? I currently have a Apple MacBook Pro "Core 2 Duo" 2.4 13" Mid-2010 model and for almost 6 months, I have been letting it sit with a battery service warning. I already replaced the battery once after getting the battery service warning and have been avoiding replacing it for as long as possible (with hopes of replacing the laptop itself). Currently, I just let it sit with the charger plugged in most of the time, because when off charger, battery life is &lt; 1hour. 

My main question is, does the macbook slow itself down or handicap itself when the battery service warning is present?

Additionally, this is the battery information under system information

Charge Information:

Charge Remaining (mAh): 1663

Fully Charged:  Yes

Charging:   No

Full Charge Capacity (mAh): 1663

Health Information:

Cycle Count:    817

Condition:  Service Battery

Battery Installed:  Yes

Amperage (mA):  0

Voltage (mV):   12405
It could, possibly a little but probably doesn't slow the CPU down. You would see high kernel task in cases when the system is self regulating. Check Activity Monitor and perhaps consider backing up and wiping the Mac.

After a clean install, you might find things speedier.