Apple's iPhone 6s. Image source: Apple. 

In 2014, Apple (AAPL 1.27%) broke with tradition and launched not one but two flagship mobile devices: iPhone 6 and iPhone 6 Plus. The iPhone 6 Plus was essentially a larger version of the iPhone 6, but with a few enhancements, namely a higher resolution display and the inclusion of optical image stabilization for still images.

With this year's iPhone 6s/6s Plus, the differences between the two devices remain the same, except this year the iPhone 6s Plus gained support for optical image stabilization with videos as well.

It would seem, though, according to a report from well-known KGI Securities analyst Ming-Chi Kuo, that next year's iPhone 7 Plus will include more system memory than the iPhone 7. Let's take a closer look at what this might imply for the next-generation iPhone.

Some memory basics
According to Kuo, the added memory in the iPhone 7 Plus over the iPhone 7 will be included for performance reasons. To understand how added memory can lead to better performance, it's important to understand the role of main memory in a computer system such as the iPhone.

Whenever an application runs, the operating system loads that application into memory so that the main processor can access the data and instructions associated with that program as quickly as possible. In fact, in iOS, if there is not enough room for the currently running application in main memory, the operating system will actually shut down other apps in order to make room for the currently running app in main memory.

As long as the applications that a user is running can fit into currently available memory, the user experience should be good.

Why would a larger-screen phone need more memory?
Right now, there isn't much to differentiate the larger iPhone from the smaller one aside from the minor camera differences and the display resolution. However, I suspect that in a bid to try to enrich its product mix/iPhone average selling prices, Apple will continue to add hardware/software features to differentiate its larger iPhones from the smaller ones.

One fairly obvious thing that Apple could introduce is split-screen multitasking in its larger iPhones beginning with the iPhone 7 Plus, a feature similar to what is currently available on the iPad Air 2 and the upcoming iPad Pro. Since such a feature should allow two, potentially resource-hungry applications to run in tandem, it could make sense to increase the amount of memory included in the device.

Could future Plus models get improved applications processors, too?
Although Kuo says that both the iPhone 7 and 7 Plus will use Apple's upcoming A10 processor, I do think that at some point down the line Apple might benefit from developing a more powerful applications processor specifically for the Plus iPhones.

For example, since the larger iPhones are generally in thicker chassis with greater volume, an applications processor specifically tailored for the larger phone could be allowed to dissipate more heat. The larger phones also have substantially larger batteries, which could also allow Apple to deliver more performance at the same battery life.

I don't think such an applications processor would have to be vastly different from a design perspective. The difference between an iPhone Plus-bound A-series processor and a vanilla iPhone-bound A-series processor could simply be one of operating frequency on both the CPU and the graphics blocks.

If Apple wanted to get really fancy, though, it could increase the number of GPU cores to better support the higher resolution display found on the Plus models.

That said, I don't think the challenge here is one of actually building the customized chips; Apple can certainly afford to hire whatever talent that it needs in order to support the development of such chips. Rather, I suspect that the difficulties associated with having two different phone chip designs would stem from having to manage the inventories of the two different chip models.

Apple probably has enough data to be able to reasonably approximate the demand mix between the regular-sized iPhones and the Plus models, but there's no doubt that such a move would introduce additional complexity that the company just doesn't feel the need to deal with.