Tucked inside the iPhone 5S when it launched on Sept. 10, 2013 was Apple’s A7 silicon . This custom silicon was tightly tied to Apple’s hardware and software, and it was also the first 64-bit processor in a mainstream smartphone.

This is Day 20 of 30 Days of iPhone, a look at the moments that shaped the smartphone era .

The iPhone’s A7 Silicon Savaged The Competition

The move to 64-bit caught the competition off guard. While 64-bit was on their radar, they saw it as something that wouldn’t happen for many years; for the current generation, it was more of a luxury than a necessity. At least until the iPhone 5S came along.

In public, the talk was about the A7’s 64-bit capability as a marketing benefit with little upside for consumers, as reported by Cody Lee at the time : “I know there’s a lot of noise because Apple did [64-bit] on their A7,” said Anand Chandrasekher, senior vice president and chief marketing officer at Qualcomm… “I think they are doing a marketing gimmick. There’s zero benefit a consumer gets from that.”:

It was a line that didn’t hold with the public. It didn’t reflect private thinking either. The carefully laid out progression of mobile silicon needed an immediate rewrite.

Qualcomm’s Snapdragon 810 was the immediate response, but it arrived with problems that would not be addressed until the 820; the chipset ran hot, performance would be throttled quickly to prevent damage from the high temperatures, and several manufacturers had to underclock the processors from 2.0 GHz to 1.2 Ghz.

The A7 Blazed A Path For iPhone, Mac and More

The A7 was a critical moment for Apple. As one of the first to use the desktop-class ARMv8 architecture , it allowed iOS to offer computational photography, intense graphics, and a 64-bit app ecosystem long before Android. It was also the first step in the Apple Silicon revolution that would lead Apple to replace Qualcomm and Intel with homegrown solutions tightly tailored to its operating systems.

This is Day 20 of 30 Days of iPhone. Yesterday, we looked at the impact of Touch ID and biometric security .