you know the amazing third-generation iPad with the Retina Display? It's gone. Apple replaced it Tuesday, a little more than six months after launching it, with a significantly updated model.
The iPad 4 uses the same chassis and overall design of its immediate predecessor, but makes a lot of changes under the hood. The Retina Display is the same, the software is the same, and the dimensions/weight are the same. pin port for the Lightning port. The FaceTime camera has also been improved.
Looking at the differences, it has an A6X processor, which Apple claims is twice as fast as the outgoing model's A5X chip. The iPad 4 has new Wi-Fi radios, which Apple also claims are twice as fast as the outgoing model's. It supports dual-band 802.11n (2.4 GHz/5 GHz) in addition to 802.11a/b/g. It is compatible with Sprint's LTE network, where the outgoing model was only available for AT&T and Verizon. The iPad 4 loses the 30-pin port for the Lightning port. The FaceTime camera has also been improved.
link