peak power while running sustained workloads will also have to double
>> Not convinced of that.
None of the battery life scenarios that Apple showed are sustained workloads consuming peak power.
Talk Time, Browsing, Video, Music, standby... all are workloads with a fixed amount of computation per frame, or in some cases (standby) no computation at all. Once the fixed portion is complete, then the rest of the frame is in sleep mode. Pretty easy to "average" a good battery life in fixed scenarios - but like I said, peak sustained cases will double in power with the kinds of gains that Apple is talking about.
Want your video or music to run twice as fast? Of course you don't. You want your imaging computation, search operation, or Facebook post to go twice as fast. Well, most of these are network limited, but lets say you want your phone to crunch through a bunch of local data in order to do a visual representation of it - say, for example, a map of the music on your phone to certain genres of music, in a local search operation to help you find music that you might like (just brainstorming for a hypothetical useful workload). Well, that will likely run with twice as much power on the new A7, or conversely, with equal performance and less power, depending on how the app is configured.
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