Why does the iPhone require less RAM than Android devices?
1. Garbage collection
In the case of Android, since it involves garbage collection it requires more memory. The Android apps use Java and as a result, Android does garbage collection. The problem with garbage collection is that memory usage grows until it’s collected, so there might be more memory allocated than necessary. That’s bad for devices with restricted memory and no option to swap.
When the garbage collector runs, it scans the heap to find memory that’s no longer being used, and that’s an expensive process, that slows down the device until is has completed.
The iPhone do not use Garbage Collection. It uses Automatic Reference Counting, which is an innovative way of managing Objective-C objects on iOS. It does away with explicit retain, release and autorelease messages, and it behaves the same on both platforms. Unlike garbage collection, ARC does not handle reference cycles automatically. This means that as long as there are “strong” references to an object, it will not be deallocated. Strong cross-references can accordingly create deadlocks and memory leaks. It is up to the developer to break cycles by using weak references.
2. User Interface
An Android user often complains about phone lag but the iOS UI runs so smooth. The main reason is that the iOS UI rendering happens in a separate thread with real-time priority but on Android, this happens in the main thread with normal priority. This means that other apps in Android can take over the processor resources and hurt basic UI interactions, translating into a noticeable lag.
3. App management
Android lets developers run processes in the background more freely than iOS. iOS kills any process when it thinks it doesn’t need to be running. Apps that play music in the background or similar can stay alive.
Android gives a lot of freedom to app developers that cause memory leaks or resource hogging background processes which means you need to be careful what you install on your Android device. Android has made some attemps to control this, such as killing apps that use too much CPU, but still, these problems can be noticed by the user.
The iOS puts a lot of limitations on the developers and what they can do causes them not to do much harm.
Apple’s iOS is optimized to run on the hardware, which is also designed and tested by Apple, and manufactured by Apple’s manufacturing partners. Android doesn’t have that level of control because the software OS developers are separate from the hardware makers