Sweet mother is this chip nice. The folks over at iFixit, with the help of Chipworks, ripped into the brains and guts of the iPhone 5S and returned with new wonders. Here’s the takeaway:
- The A7 is the first use of a 64-bit processor in a smartphone. Based on AnandTech’s review, it seems that the bulk of the A7’s performance gains do not come from any advantages inherent to a 64-bit architecture, but rather from the switch from the outdated ARMv7 instruction set to the newly-designed ARMv8.
- The modern ARMv8 instruction set was designed for a 64-bit architecture. It does away with the legacy support of the last 20 years, which increases efficiency, improving performance without sacrificing battery life.
- “We have confirmed through early analysis that the device is fabricated at Samsung’s Foundry. We suspect we will see Samsung’s 28 nm Hi K metal Gate (HKMG) being used.”
- But wait! It turns out that the A7′s “gate pitch” — the distance between each transistor — is 114 nm, compared to the A6′s 123 nm.
- Those 9 nm are a big deal. Looking to improve on their current 32 nm process, Apple decided to make the A7 with the same 28 nm process as the eight-core Samsung Exynos 5410, the current flagship CPU for Samsung’s own Galaxy line.
- So what does that translate to? Applying some mathematrickery (28^2 divided by 32^2 = 784/1024), this seemingly small change equates to having the same computing power, but in 77% of the original area. And given that the A7 processor is larger in area than the A6, that means even more processing power to lead a healthy, smartphone-laden lifestyle.
- The A7 transistor level die photo reveals all one billion plus transistors on a 102 mm2 field.
The teardown also looked at the M7 chip and associated accelerometer, gyroscope and magnetometer, along with the iSight Camera, Wifi Module, LTE Modem, and RF and PA components. In case you’re interested in what’s behind that shiny gold casing, anyways.