I hadn't even thought about the amount of memory a 64bit system brings to the table.
I could be wrong and probably am, but to me and my limited knowledge of 32bit vs 64bit... It is more of a matter of precision and won't help a "phone" app out, unless we're talking about a game or CAD and even then I don't think it will benefit an app on a phone's scale.
I think it's Apple paving the way to the future. At this point there's not much of an advantage to a 64 bit architecture on a phone, but there will be before too long. I would imagine we'll see 64 bit Android phones before too long, and probably WP sometime in the future. I don't criticize Apple for moving in this direction, but I have to question their marginally deceptive marketing around it.
It's all a bit misleading. A 64 Bit CPU will address more than 4 GB, but not even many PC applications need that. The ARM CPU's in Windows Phone already have 64 bit registers, so you can fit 4 16 bit number calculations into one CPU instruction using SIMD.
ARMv8-A introduces 64-bit architecture support to the ARM architecture and includes:
64-bit general purpose registers, SP (stack pointer) and PC (program counter)
64-bit data processing and extended virtual addressing
Two main execution states:
AArch64 - The 64-bit execution state including exception model, memory model, programmers' model and instruction set support for that state
AArch32 - The 32-bit execution state including exception model, memory model, programmers' model and instruction set support for that state
The execution states support three key instruction sets:
A32 (or ARM): a 32-bit fixed length instruction set, enhanced through the different architecture variants. Part of the 32-bit architecture execution environment now referred to as AArch32.
T32 (Thumb) introduced as a 16-bit fixed-length instruction set, subsequently enhanced to a mixed-length 16- and 32-bit instruction set on the introduction of Thumb-2 technology. Part of the 32-bit architecture execution environment now referred to as AArch32.
A64 is a 32-bit fixed-length instruction set that offers similar functionality to the ARM and Thumb instruction sets. Introduced with ARMv8-A, it is the AArch64 instruction set.
ARM ISAs are constantly improving to meet the increasing demands of leading edge applications developers, while retaining the backwards compatibility necessary to protect investment in software development. In ARMv8-A there are some additions to A32 and T32 to maintain alignment with the A64 instruction set.
It's all about marketing, Apple is a marketing company that happens to do tech, not a tech company that is good at marketing.
Apple can't say they are first at many things because for the past few years their releases have been middle of the pack but they can now say they are one of the first if not the first to offer a 64 bit phone processor. Right now it means absolutely nothing but in the future it will make a difference, by the time it does matter everybody else will be offering it too and it won't be as big of deal Apple did it. This is another thing most people that buy the phone have no idea what a 64 bit processor is or what it does to the phone. All the camera features Apple added have lalready been in phones so again Apple released a middle of the pack phone. Apple will sell both the new phones because of their marketing, they have a way of telling everybody you need the new iPhone. They market....people buy....Apple makes money, Apple is a business, it's their job to make money and you can't fault them for that but we all know they don't sell because they offer stuff nobody else does. Well except $29 flexible cases.