Originally Posted by Gatorguy
Honest question Soli: Has 64-bit improved your iPhone user experience yet, and if so in what way? I haven't seen much in the way of comments about real-world differences.
Absolutely, but in the same a few hundred extra MHz might improve an experience or a better H.264 decoder might reduce power consumption for video playback by 10%, in that you may not notice it until it's no longer there.
I did side-by-side tests from my iPhone 5 and the 5S. Booting up the 5S was a little faster but that's only done as a baseline since you really only should be booting your phone after an update. The app launches I tried (not so much with large games) were faster but it was a difference that I wouldn't have noticed them if not for the side-by-side comparison. The areas where I saw the most performance gain was with the app closing but this can also be seen within certain apps. This is one area where the new ISA really shines for Obj-C and where you can easily perceive the difference without a side-by-side comparison. So why do you care about this? It allows other operations to take place sooner and have more resources available and uses less power.
Mike Ash explains it better than I ever could but the benefits are definitely real.
"In short, the improvements to Apple's runtime make it so that object allocation in 64-bit mode costs only 40-50% of what it does in 32-bit mode. If your app creates and destroys a lot of objects, that's a big deal."
"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 release operations 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."