For some analysts, killer features of the iPhone 5S on its September release date are pretty much certain - they have a general peg on how it looks, how powerful it is and what are its incredible capabilities.

This is the exact case in a new research note issued by KGI Securities analyst Ming-chi Kuo. Considered as one of the most credible Apple forecasters, Mr Kuo is betting that Apple will religiously follow its A-series chip processing pattern for the 2013 flagship smartphone.

The 5S will be an A7-powered iOS device, with the likelihood of 64-bit processing capabilities, the analyst said.

The whole SoC processes will stand on the newer ARMv8 architecture, which will boost both the 5S's processing might and graphic prowess plus some 20 per cent more muscle in overall efficiency when compared to the A6 chips used on the iPhone 5, Mr Kuo was reported by Apple Insider as saying.

But the RAM provision will remain at 1GB as "we reckon A7 will upgrade memory bandwidth spec to LPDDR3 from LPDDR2 adapted by A6, in an effort to improve system performance," said Mr Kuo as reported by MacRumors.

Another key upgrade is the expansion of the built-in storage as the KGI report hinted the possibility of an iPhone 5S premium edition that will offer a capacious 128GB of space, which will be encased in a gold shell.

"We also forecast the new model will add a new look, a golden casing, and a new option for larger 128GB storage, to offer greater differentiation from iPhone 5," Mr Kuo said.

However, it was unclear if the new configuration will be the fourth storage option for the iPhone 5S or Apple will simply retire the 16GB versions and offer three variants instead - the 32GB, the 64GB and the new 128GB.

Such move will more than patch up the iPhone's lack of memory expansion slot, which some experts perceived as one major advantage that Android has over the iOS device, which includes previous and upcoming builds.

The latest KGI forecast should see confirmation on the supposed Sept 10 media event that Apple had announced, in which the iPhone 5C (or iPhone Lite) and the revamped iOS 7 are also set for unveiling.

Actual release date should follow within the same month though Apple could opt to rollout the iPhone 5S on the same day as it races to post record sales figures by the end of September or Q3 2013.