While 64 bit mobile processors are certainly a significant step forward for mobile computing, at present 64 bit processors for mobile are a gimmick because it's going to be a long time before the capabilities of such a chip can be taken advantage of. All this means is that we'll be seeing phones hit the market that have 16gb plus of RAM and well, I think we are a long way off seeing phones with that much memory hit the market. We are only seeing phones with 3gb of RAM that require equally as large batteries to power them like the Samsung phones.
It took years for the PC market to transition from 32 to 64, and it'll take years for mobile to do the same. The amount of time it will take means competitors shouldn't worry because by the time 64 bit processors make sense, everyone will be manufacturing one. Sure memory addressing is just part of the picture and a 64 bit processor means data bandwidth is double that of a 32 bit chip which can be seen below 4gb of RAM, I think at present the iPhone isn't taking advantage of such improvements.
The processor, in 32bit mode, offers more on-core registers, and a beefier instruction set.
Programs compiled by a compiler aware of those distictions should significantly, measurably, perceptibly outperform those compiled for the older more constrained architectures.
It took years for the PC market to transition from 32 to 64, and it'll take years for mobile to do the same. The amount of time it will take means competitors shouldn't worry because by the time 64 bit processors make sense, everyone will be manufacturing one. Sure memory addressing is just part of the picture and a 64 bit processor means data bandwidth is double that of a 32 bit chip which can be seen below 4gb of RAM, I think at present the iPhone isn't taking advantage of such improvements.