For a company so obsessed with secrecy, it's rather ironic that Apple (NASDAQ:AAPL) can't surprise investors and consumers anymore thanks to the company's omnipresent rumor mill. For instance, every aspect of the iPhone 5 was leaked in advance, and there were no surprises when the new flagship device was officially unveiled.

Over the past few months, details of the purported iPhone 5S have been steadily making their way to market. Investors are expecting the next model to include a fingerprint sensor for biometric security (and possible payments service). Following the same two-year design cycle, the body may remain the same, while internals like the processor and camera will get appropriate bumps.

The latest Apple rumor is catching investors by surprise, but it also makes no sense.

More trouble than it's worth
Weiphone is reporting that Apple will further increase the resolution of the iPhone 5S, doubling the total pixels from about 730,000 to approximately 1.5 million. The Chinese site also claims that Apple will make the device's bezel even slimmer, taking cues from the iPad Mini.

There are several reasons why cramming 1.5 million pixels in doesn't pass the sniff test. Assuming that Apple sticks with a 4-inch display (it just added that size less than a year ago and the larger iPhone isn't expected until next year), increasing the resolution would introduce another layer of fragmentation into iOS while app developers are still in the process of transitioning content to the iPhone 5's taller display.

Here are some theoretical scaled resolutions for a 4-inch display.

Resolution

Scaling Factor

Total Pixels

Pixel Density

1,136 x 640 (current)

1 (current)

727,000 (current)

326 PPI (current)

1,590 x 896

1.4

1.42 million

456 PPI

1,647 x 928

1.45

1.53 million

473 PPI

1,704 x 960

1.5

1.64 million

489 PPI

Source: Apple and author's calculations. Some figures rounded. PPI = pixels per inch.

Getting to 1.5 million pixels would require non-integer scaling to ensure backwards compatibility with existing apps, and the associated algorithms could put a drag on performance. Apple uses extensive scaling in Retina MacBook Pros, and warns that using scaled resolutions affects performance for precisely this reason.

The whole pitch for the original Retina display was that users couldn't discern individual pixels at normal viewing distances -- increasing pixel density up to above 450 PPI seems like overkill. That hasn't stopped rivals from upstaging Apple with denser displays. Here are the top two 2013 models within the Android army.

Device

Resolution

Total Pixels

Pixel Density

Samsung Galaxy S4

1,920 x 1,080

2.07 million

441 PPI

HTC One

1,920 x 1,080

2.07 million

468 PPI

Sources: Samsung and HTC. These models have different display sizes, resulting in different pixel densities.

Apple could increase to stay abreast with rivals, but considering the overkill of this spec, a competitive response doesn't seem necessary. Doing so would entail sacrifices with developers, app compatibility, and performance. Jamming 1.5 million pixels into a 4-inch display would be more trouble than it's worth.

Fool contributor Evan Niu, CFA, owns shares of Apple. The Motley Fool recommends Apple. The Motley Fool owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.