It was a big deal when Apple doubled the resolution of the iPhone screen to 960 x 640 pixels in mid-2010. Less than three years later, the leading Android phone makers have inched their way upwards from 720p to the absurd pixel density of 1080p phone screens. They're big--5 inches seems to be a standard Android screen size, these days. They're dense--the pixels are barely visible. And they're beautiful. But at what cost?
LG's leaked Optimus G Pro upgrades the original Optimus G's 1280x768 screen to 1080p, but also increases the battery size from a pretty standard 2100 mAh to a crazy 3000 mAh. That gives the phone a battery nearly as large as the Droid RAZR Maxx. So no big deal, right? The screen needs more battery power, and the phone gets a larger battery. Sure--but in some cases, phonemakers aren't compensating for the increased battery drain of a high resolution screen.
Recent example: HTC's Droid DNA. Ars Technica tested out the phone and found that the DNA's 1080p display negatively affected its scores in GL Benchmark compared to the LG Optimus G, even though both phones use the same 1.5 GHz Snapdragon S4 SoC with Adreno 320 GPU. Worse news: in a battery run-down test, the Droid DNA fared worse than the Optimus G and the Galaxy S III, which all run on Snapdragon S4 chips (though the Galaxy S III's is an older version). The DNA's battery is 4 percent smaller than the other phones'--2020 mAh vs 2100 mAh--but it died 22 percent faster than the Galaxy S III and 18 percent faster than the Optimus G. Uh-oh.
Ars also noticed that the phone got piping hot when it was under full load. Any number of factors could be at fault there, but the GPU test made it clear that running a 1080p display is hard work for a mobile GPU; there are a million more pixels to compensate for than there are in a 720p display.
In addition to LG and HTC, Sony has a 1080p smartphone, the Xperia Z, releasing in 2013. And you can bet that Samsung's next Galaxy phone will be competing with the most advanced phones on the market when it's released. The Xperia Z runs off a 2330 mAh battery, which may give it a slight runtime edge over the other phones mentioned above. But it seems like 1080p screens will erode, or at least balance out, battery life gains made by more efficient processors and LTE chips.
By sticking with 720p screens this year, Android phonemakers could easily offer better battery life than ever before. By migrating towards denser displays, those gains will be minimized. And in most cases, people won't even be able to tell the difference.
Higher resolution displays promise sharper text, but 1080p might actually make some things look worse on Android phones in the short-term. Android apps are designed to scale to many resolutions, but Ars noticed some fuzzy icons on the DNA's screen. 2013 will probably be an adjustment period, in which developers make sure their apps can scale to higher resolutions on smartphones. And some Android users will be adjusting, too, wondering why the battery life of their brand new phone is worse than the one they bought in 2012.