iPhone 4 VS iPhone 3GS

Iphone 4	iPhone 3GS
High-resolution Retina display 960-by-640 resolution 326 ppi Multi-Touch	480-by-320 resolution 163 ppi Multi-Touc
5 megapixels LED flash Backside illumination sensor Autofocus Tap to focus Front camera with VGA resolution	3 megapixels Autofocus Tap to focus
HD video recording Tap to focus while recording LED light	VGA video recording Tap to focus while recording
Multi-Touch 802.11b/g/n Wi-Fi3 7.2-Mbps HSDPA 5.8-Mbps HSUPA GPS Three-axis gyro Apple A4 processor Dual-mic noise suppression	Multi-Touch 802.11b/g Wi-Fi 7.2-Mbps HSDPA GPS Accelerometer
Talk time: Up to 7 hours on 3G; up to 14 hours on 2G Standby time: Up to 300 hours Internet use: Up to 6 hours on 3G; up to 10 hours on Wi-Fi Audio playback: Up to 40 hours Video playback: Up to 10 hours	Talk time: Up to 5 hours on 3G; up to 12 hours on 2G Standby time: Up to 300 hours Internet use: Up to 5 hours on 3G; up to 9 hours on Wi-Fi Audio playback: Up to 30 hours Video playback: Up to 10 hours