Originally Posted by nikon133
Don't buy the hype.
Stretching architecture from 32 to 64 does not boos performance by default. Some tasks are positioned to take advantage of 64-bit registers - encryption comes to mind - but many are not.
In addition, there is additional complexity of emulation layer required to run 32-bit apps on 64-bit OS. This might introduce a small performance hit (compared to same software running on same hardware with 32-bit OS installed) as well as some compatibility issues.
This new Apple SoC is advertised to be up to 2x faster in CPU and GPU compared to iPhone 5 SoC. I'd be surprised to see it flat-rate 2x faster in everything... but even then, it is still far cry from modern desktop performance. Regardless of "desktop performance" marketing talk.
At this stage, 64-bit architecture is foundation for the future, but with not much short term advantage for iPhone 5s owners - if any. Pretty much every article I came across seems to agree with this.
Tell that to Seymour Cray, I agree going to 64 bit will no automatically double the performance of every task but many task can get benefit from it and since iOS got the richest sets of multimedia and signal processing oriented APIs, current apps will gain some benefit from the 64bit iOS 7 thru API call. Those are things Apple has done many times in his history; adding functionality and optimization thru API upgrades. Like the cut and paste feature in example, once they added functionality, it was available even in older apps pre-dating the features without any intervention of the apps developer. The CPU usage of iOS apps that use standard UI are mostly made of API calls, with Xcode you can actually create a full browser apps without a single line of code, only by linking UI elements directly to API call in the Interface Builder.
In addition, you are wrong. the ARM 64bit instructions set is an extension of the current 32 bit instructions, just like on x86 processors, your 64bit PC doesn't have to emulate 32 instructions for running 32 bit programs, it run it directly and use only 32 bits of the 64bit available register. But 64bit versions of Windoze does have to run his shit in a VM (SysWoW64), which isn't the case for OSX and iOS.
Regarding the performance boost, Apple is very secretive and gives very little technical detail but we know they double the number of register and double their size. I'm pretty sure other things like the RAM channels and I/O have been upgraded too. Its pretty conceivable to double the overall performance solely by doubling RAM channels and I/O bandwidth alone.
Apple has done bigger architecture switch in the past, if we took the PowerMac G5 for example, at time of launch every reviews praise how fast everything was on that new computer even if no apps was updated yet for the G5. Of course things could be different for the iPhone, but one thing for sure, 64bit is there to stay.
Edited by BigMac2 - 9/12/13 at 6:10pm