The A5 chip within iPad 2 and iPhone 4S has limited RAM due to battery life concerns, according to a surprising source - rival Microsoft. So far, Apple has not commented on why the A5 has the same RAM capacity as its predecessor the A4, when some of the competitors have included 1 GB of RAM in their mobile devices for a while now.
Bill Karagounis, the group program manager of Microsoft's Performance team, quoted by Steven Sinofsky explained in detail why using less RAM is critically important (opens in new tab): "minimizing memory usage on low-power platforms can prolong battery life" and by doing so offers a possible answer regarding the A5, which Apple has failed to mention.
The Windows and iOS environments are different however, and users do not face the same problems. On the other hand, Apple typically designs devices built for specific tasks: either a mobile tablet or a handset built to operate on low power for a longer time, or full powered hardware like MacBooks which need recharging after a few hours. Moreover, an A5 chip with more RAM would not only drain battery faster but would also make mobile devices more expensive.
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