Your battery is aging, and likely needs to be replaced. When batteries get old, they are unable to deliver as much power when the phone is running intensive apps or doing something strenuous. Now your phone is slowing itself down so it won’t need to deliver as much power. You’ll notice your phone is slower now, and I’d recommend replacing the battery.
mrduncansir42 t1_j1f6j5h wrote
Reply to What caused this? by TrashAtEverything_
Your battery is aging, and likely needs to be replaced. When batteries get old, they are unable to deliver as much power when the phone is running intensive apps or doing something strenuous. Now your phone is slowing itself down so it won’t need to deliver as much power. You’ll notice your phone is slower now, and I’d recommend replacing the battery.