ValueWalk's Christopher Morris recently penned a piece exploring potential features in a next-generation Apple (NASDAQ:AAPL) iPhone 7 (although I'm going to refer to it as the 6s). One feature he discussed in particular was a move to a quad-HD (2560-by-1440) display in the next generation iPhone 6s Plus. According to Morris, this would allow Apple to keep pace with rivals, differentiate the device from a potential 6s with a full-HD (1920-by-1080) display, and "retain an acceptable pixel density."
While I believe these arguments seem plausible on the surface, I very much doubt that Apple's next phablet will include a quad-HD display in the next generation iPhone "Plus" model. Here are three reasons why.
According to Morris, the feature Apple should be focused on improving most is battery life, remarking that "the iPhone series still suffers from pretty weak battery life." If Apple were to move to a 2560-by-1440 LCD in the iPhone 6 Plus, it would either need to include a larger battery to compensate for the additional power draw, or battery life would suffer.
Since Apple probably doesn't want to shorten the battery lives of future devices relative to the current iPhone 6/6 Plus, and given that larger batteries generally cost more and take up additional physical volume in the device, this may not be an attractive design choice for the next generation of iPhones.
A meaningless cost increase
Higher resolution panels are generally more expensive to build than lower resolution panels of the same quality. If Apple were to include a quad-HD display in the next iPhone Plus, then this would undoubtedly increase the cost per unit of the device.
This isn't to suggest that Apple is completely averse to making improvements that cost money, but given that Apple runs its business to extract maximum profit, it needs to make upgrades very judiciously. The pixel density on the current iPhone 6 Plus is 401 pixels-per-inch which is extremely good. While some users might notice an increase from these levels, I argue that we're close to the point of diminishing returns.
Further, there's more to screen quality than pixel density. There are quad-HD displays that look awful and 1334-by-750 displays (such as the one found on the smaller iPhone 6) that look great. If Apple is going to increase its iPhone cost structure with a more expensive display, it should continue focusing on improving colors, brightness, contrast, and other things that actually matter beyond numbers on a spec sheet.
This would increase the demand for graphics power
Finally, something that people often don't talk about is that higher resolution screens increase the demands on the graphics/display portions of the mobile processor. In the world of PC gaming, for example, it often takes top-of-the-line stand-alone graphics processors that consume hundreds of watts of power to play the latest 3D games in quad-HD resolution at full image quality.
Mobile graphics processors, in comparison to these PC-oriented graphics add-in boards, are just plain weak since they're built to be cheap and to consume relatively little amount of power. At this point, I think it'll be a very long time before mobile devices will have graphics processors capable of delivering the kind of richness and fidelity that are typical in modern PC games at high resolutions.
What game developers can (and often) do is simply have games render at lower resolutions than the display's native one, which lowers the demand on the mobile graphics processor. However, in this case, what's the point of the high pixels-per-inch screen if any graphically intensive applications can't actually render at this resolution?
Additionally, we can tie this back into the battery life argument: if the mobile graphics processor is trying to maintain a certain frame-rate at a higher resolution, it could probably consume less power if it were trying to maintain that same frame-rate at a lower resolution. So, power use goes up not just from the display, but from the chip powering the phone -- at least in graphically intensive situations -- as well.
See how silly the pixels-per-inch race is?
I'm not against resolutions in mobile devices improving over time; higher resolutions are nice when the cost structure, power consumption, and computing/graphics power can support them and a real user experience benefit is delivered.
However, I get a sense that companies like Samsung, LG, and so on are pushing higher resolution displays simply for the sake of selling points for their own devices, which in turn pressures their mobile device display customers to buy up to keep up.
The other Android vendors, who try to differentiate solely on hardware specs (even though they all have access to the same hardware), will keep playing the pixels-per-inch game, but I'm sure Apple will ignore it, only moving to higher resolution panels when it makes economic and technical sense.