In addition to the processor speeds, the analyst also said that both iPhone 6 models could feature different touch modules. Reuters

With the supposed September unveiling of Apple Inc.’s (NASDAQ:AAPL) iPhone 6 getting closer, an analyst has predicted that the processor speed will be a major differentiating factor -- other than the screen size -- between the two rumored versions of the next-generation iPhone.

Apple is widely expected to release two bigger iPhone 6 versions this year, featuring 4.7-inch and 5.5-inch screen sizes, with the latter believed to sport a more powerful processor, Cowen & Co. analyst Timothy Arcuri said in a note to investors, citing sources at Apple’s Asian suppliers.

While Arcuri did not provide more details about the two processors, the improvements are expected to be similar to moves by Apple in the past. The company’s iPad Air was powered by an A7 processor clocking at 1.39 GHz while the iPad mini with Retina display featured the same chip clocking 1.29 GHz, Apple Insider reported.

Arcuri also said that the processor inside the 5.5-inch iPhone 6 could come with a larger die, suggesting that the bigger model will use a larger array of graphics-processing cores. There is another possibility that Apple could produce the two processors -- expected to be the new A8 -- in different fabrication facilities, using different processes, Apple Insider reported.

In addition to processor speeds, the analyst also said that both iPhone 6 models could feature different touch modules. The iPhone’s touch modules are currently being supplied by Taipei-based TPK Holding Co. Ltd (TPE:3673), which was recently rumored to be the manufacturer of silver nanowire-based parts for the rumored iWatch.

Reports surfaced last week claiming that Apple could launch the 4.7-inch version of the iPhone 6 during its traditional September release timeframe, while the bigger 5.5-inch model could arrive in December, along with the iWatch.

A report from Taiwanese news publication UDN recently said that the production of the 4.7-inch iPhone 6 is already underway as the device is expected to be ready for launch in September, while the bigger 5.5-inch model may not even enter production by that time.