All iPads: iPad 3/4 battery compared to the iPad 2 with Screen Off Playing music/wifi streaming

[cyber16]

With the 70% larger capacity battery within the ipad 3/4 over that of the ipad 2, should it not last allot longer playing music & wifi streaming music if the screen is in sleep mode? Theoretically, one would think sleep mode is not just shutting down the led backlight, it should also be clocking the GPU way down & nearly shutting most power off to the LCD & GPU while in sleep mode, NO?

The CPUs A5 vs A5x has very little difference in power needs/usage.

The Retina screen and the gpu is where the major differences are, driving them extra pixels. Therefore, has anyone compared the two given the above scenarios?

Or is apple’s IOS simply not smart enough to power conserve with these components while in what should be a given power saving mode when screen is off/dark