Apple’s dual-core A5 processor (which is present in both the iPhone 4S and iPad 2) boasts 512 megabytes of RAM – a relatively meagre figure, compared with the full one gigabyte many other competing smart phones possess. While Apple hasn’t publicly discussed the A5′s RAM,¬†Steven Sinofsky (of Microsoft) has been able to explain why Apple chose to load-up both iOS devices with just a half-gigabyte.

According to Sinofsky (via Apple Insider), Apple likely limited the RAM of the A5 to 512 megabytes because it wanted to preserve the battery life of its A5-equipped iOS devices. In a blog post, he wrote:

Having additional RAM on a tablet device can, in some instances, shave days off the amount of time the tablet can sit on your coffee table looking off but staying fresh and up to date.

In short, the more RAM you’ve got loaded into your iOS device, the more that mobile device’s battery life is reduced. If the iPad 2 and iPhone 4S can manage without that extra half-gigabyte (which they obviously can), then Apple obviously isn’t going to include it for the above reason.

Both the iPhone 4S and iPad 2 boast impressive battery lives, which are key aspects of the handset and the tablet (especially when the earlier iPhone models could barely make it through day without a quick, convenient recharge sometime around mid-afternoon).

And if that demo of Infinity Blade 2 (which Epic Games presented at Apple’s iPhone event) is anything to go by, the iPhone 4S doesn’t really miss that half-gigabyte of RAM anyway.