An electronic device with a touch screen display that includes capacitive sensing to determine the point of contact between the display and an input device. The device also includes a graphics circuit for rendering images on the touch screen display. The graphics circuit may be inactivated when not in use. The inactive mode provides a variety of advantages, such as a lower power drain on the power source. The device is further configured to sense the approach of an input device in proximity to the display. The device is configured to start activating the graphics circuit upon sensing the approach of the input device prior to contact with the display. The timing of the activation improves responsiveness of the electronic device.