We were not sure yet this news is eagerly awaited. It’s odd though, I think I’ve observed this before. In some cases rehashed press releases still contain bits of new details that we didn’t have before.
I didnt think battery density would improve as much as it did. And I definitely didnt think Apple would integrate a large 4MB cache on its SoCs , thereby reducing the need for a super wide memory interface. The combination of those three things made giving the iPad mini a Retina Display possible, and thats exactly what Apple did this year. Its called the iPad mini with Retina Display, and unlike the iPad Air , it looks a lot like its predecessor. Youd be hard pressed to notice the 4.1% increase in thickness (+0.3mm) or the 7.5% increase in weight (+23g). Even if you did, what those slight gains net you is more than worth the effort. From top to bottom: iPad mini, iPad mini with Retina Display, iPad Air The Retina mini now features a 44% larger battery (23.8Wh). Thats nearly the same battery capacity as the original iPad (25Wh), but in a chassis with only 1/3 of the volume.
Noted from: http://www.anandtech.com/show/7519/apple-ipad-mini-with-retina-display-reviewed