So why didn’t the iPhone 4S go from 512 MB to 1 GB of RAM? Only Apple knows for sure, but I found this blog post from Microsoft’s Steven Sinofsky interesting:
Something that might not be obvious is that minimizing memory
usage on low-power platforms can prolong battery life. Huh? In any
PC, RAM is constantly consuming power. If an OS uses a lot of
memory, it can force device manufacturers to include more physical
RAM. The more RAM you have on board, the more power it uses, the
less battery life you get. 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.
I’d always thought that the trade-off with more RAM was simply a matter of price. More RAM costs more money. I’d never thought of it as a factor in battery life.