Full information on iPhone5S's ARM64 64bit processor

Read this article today :

Here is the complete information about what you need to know on Apple's ARM64 64-bit processor in iPhone5S as an iOS Developer. 

Here's my favourite stuff from the article :

"  Adding it all together, it's a pretty big win. My casual benchmarking indicates that basic object creation and destruction takes about 380ns on a 5S running in 32-bit mode, while it's only about 200ns when running in 64-bit mode. If any instance of the class has ever had a weak reference and an associated object set, the 32-bit time rises to about 480ns, while the 64-bit time remains around 200ns for any instances that were not themselves the target.  "

Here's the conclusion from the article :

"  The "64-bit" A7 is not just a marketing gimmic, but neither is it an amazing breakthrough that enables a new class of applications. The truth, as happens often, lies in between.

The simple fact of moving to 64-bit does little. It makes for slightly faster computations in some cases, somewhat higher memory usage for most programs, and makes certain programming techniques more viable. Overall, it's not hugely significant.
The ARM architecture changed a bunch of other things in its transition to 64-bit. An increased number of registers and a revised, streamlined instruction set make for a nice performance gain over 32-bit ARM.
Apple took advantage of the transition to make some changes of their own. The biggest change is an inline retain count, which eliminates the need to perform a costly hash table lookup for retain and releaseoperations in the common case. Since those operations are so common in most Objective-C code, this is a big win. Per-object resource cleanup flags make object deallocation quite a bit faster in certain cases. All in all, the cost of creating and destroying an object is roughly cut in half. Tagged pointers also make for a nice performance win as well as reduced memory use.
ARM64 is a welcome addition to Apple's hardware. We all knew it would happen eventually, but few expected it this soon. It's here now, and it's great.  "