32bit vs 64bit: What's the benefit?

[Kalloud]

Hi.
So with the move to 64bit with the upcoming iOS 11, and iOS 10.3.2 which drops support for 32bit devices, I was wondering why would we need 64bit apps?
Are 32bit ones slow or do they use more ram or something?
Or is this another marketing gimmick?

 

[clukas]

Well technically we already are on 64bit. The transition happened with iOS7 which was the first 64bit iOS. Whats happening is that apple is dropping support for 32bit apps. Amongst some of the reasons why we are moving to 64bit are RAM limitations, a 32bit processor can access a maximum of 4GB of memory and as iOS devices (iPad Pro, iPhone etc) become more RAM hungry apple is future proofing. Another reason is how processors handle calculations, a 64bit processor can access and manipulate data in 64-bit chunks rather than just 32 which is more efficient. Its hard to say whether there is any visible performance improvement on an average iOS app, however the transition was needed as iOS devices will need more than 4GB of RAM in the future.

 

[Fireagle]

If I remember correct, you need 64Bit for touchid. The unlocking with 32bit would be too slow.

 

[JohnnyGo]

A couple of important reasons come to mind:
- performance (which translates into better battery life)
- storage waist (reducing the need for 32bit code / APIs in OS and, more importantly, in apps)
- reducing the number of supported hardware (breaking from old h/w and thus reducing testing/coding for app developers)
- cleaning app store from old/dated software (that usually do not perform well or are not up to latest security standards)

 

[rbart]

Since iOS9, storage is already optimized.
You only download the binary package for your platform 32 OR 64bit depending on you iOS device.

 

[SoN1NjA]

- storage waist (reducing the need for 32bit code / APIs in OS and, more importantly, in apps)

Yes, as @rbart said your device only downloads the version of the app your device needs, so your iPhone 7 doesn't have the iPhone 7 Plus files