Apple has started distributing both the iPhone SE and the 9.7-inch iPad Pro to journalists, and one of the first things to come to light has been the amount of RAM in each device. Memory in iDevices has a big impact on performance and general usability, but Apple almost never actually talks about it so we need to have hardware in hand before we can get the full story.
The good news is that the iPhone SE has the same 2GB of RAM as the iPhone 6S and 6S Plus despite its smaller size and lower price. The not as good news is that the 9.7-inch iPad Pro has the same 2GB of RAM as the iPad Air 2, not the 4GB of RAM on offer in the 12.7-inch version.
RAM doesn't have quite the same effect in an iOS device as it does in laptops and desktops—iOS was originally designed for low RAM devices and even though current iPhones and iPads have much more RAM than the 128MB in the first iPhone, the OS is still aggressive about ejecting apps from memory. Giving an iPhone or iPad more RAM doesn't necessarily speed up general performance, but it does mean that apps and browser tabs need to be ejected from memory less often. Today this is particularly beneficial in Safari, which needs to reload tabs when they're ejected from RAM—at best this process adds a couple of extra seconds to what ought to be a simple tab switch, and at worst you don't have connectivity and so can't see the tab you're trying to open.
For the iPad Pro, the consequences could be more far reaching, just because developers are going to be able to do things with 4GB of RAM that just won't fit into 2GB of RAM. And Apple has occasionally stopped supporting certain devices because of RAM limitations rather than raw performance limitations—the original iPad had 256MB of RAM and didn't get either iOS 6 or iOS 7, while the 512MB iPhone 4 with the same A4 chip got both updates. It's going to be fine for now (many actively supported iPads still have 1GB or even 512MB of RAM), but it could one day be a problem nevertheless.
