Released in November 2012 alongside the iPad Mini, the 4th generation iPad - officially called the iPad with Retina Display - is in many ways identical to the iPad 3 (officially known as the New iPad). Similarities include the dimensions and the Retina screen that gives this model its name, which has 3.1 million pixels - that's four times the number of pixels in the iPad 2 and a million more than an HDTV.
The main differences between this iPad and the now-discontinued iPad 3 are the processor, the Lightning connector and the camera specs. Firstly the Retina Display model uses an Apple A6X processor, which they reckon is twice as fast as the A5X previously used. On the subject of speed one of the controversial changes to this iPad and the Mini is the use of a different connector, the Lightning, instead of the 16 pin version we were used to - not compatible with your old leads perhaps but as an all-digital connector it's more future-proof.
The iPad with Retina Display has 2 cameras - the main iSight camera is the same 5 megapixel model as in the iPad 3 but with a back-illuminated sensor which will improve the quality of pictures taken in low light. The front-facing camera is the bigger improvement, a FaceTime HD camera with support for up to 720p video and 1.2 megapixel photos.
Connectivity-wise the Wi-Fi on this 4th generation model is improved to allow up to twice the speed of the iPad 3 and the inbuilt modem supports 4G on 1800MHz, the frequency used by EE.
