Thanks to the guys over Chipworks and their detailed inspection of the board of the iPhone 5s, we now know the full specifications of the chipset of Apple's latest flagship. As you probably know since day one, the new iPhone 5s runs on a new Apple A7 SoC that utilizes a 64-bit processor. This new CPU turns out to be a dual-core unit clocked at 1.3GHz and uses the latest ARM v8 64-bit cores....
Source: http://www.gsmarena.com/iphone_5s_specs_revealed_arm_v8_cpu_powervr_series_6_gpu-news-6849.php
