Apple is taking a major stride that will allow developers to improve the performance of their apps on iPhones and iPads, by giving apps the ability to access more of a device's memory or RAM starting later this fall.
Currently, apps are limited to the amount of RAM they can use, regardless of the amount available on the device. For example, despite the highest-end M1 iPad Pro featuring 16GB of RAM, on iPadOS 14, apps are limited to only use 5GB. 16GB of RAM is the highest amount of RAM ever offered in an iPhone or iPad, and the 5GB limitation means that apps aren't able to utilize even half of what the iPad Pro has to offer.
In the second betas of iOS and iPadOS 15, released to developers yesterday, Apple is introducing a new entitlement that developers may request that will expose their apps to more memory. Apple says that this entitlement will inform the system that an app "may perform better by exceeding the default app memory limit." Apple's developer documentation doesn't specify how much extra RAM an app may be exposed to and also says this is limited to "supported devices."
Add this entitlement to your app to inform the system that some of your app's core features may perform better by exceeding the default app memory limit on supported devices. If you use this entitlement, make sure your app still behaves correctly if additional memory isn't available.
While Apple doesn't specify the amount of extra RAM an app may request, the wording of the documentation, which advises developers to use a function to "determine the amount of memory available," suggests the ceiling of memory apps may request may be relatively high.
It's unlikely that Apple will allow developers to utilize the full amount of memory on a device. While that scenario may be useful for high-end professional apps on the iPad Pro, it would significantly slow down the system and make it harder to multitask with different apps. Users of the iPad Pro, and more so recently thanks to the M1 iPad Pro, have complained that iPadOS is limiting the true potential performance of the iPad.
Despite many users' hopes, iPadOS 15 didn’t introduce any significant features that took full advantage of the hardware of the iPad, specifically the M1-powered iPad Pro. However, the ability for apps to request access to more on-device RAM will go a long way in apps being able to utilize even more of what a device has to offer.
The new entitlement is available for developers to test, but it won't be made available to apps on the App Store until this fall when iOS and iPadOS 15, alongside watchOS 8, tvOS 15, and macOS Monterey are made available.
