Samsung’s new $3.6 billion factory in Austin has now kicked manufacturing into full tilt and is dedicated almost entirely to producing Apple’s A5 chip shipping in the iPhone 4S and iPad 2.

Reuters reports:

The A5 processor – the brain in the iPhone 4S and iPad 2 – is now made in a sprawling 1.6 million square feet factory in Austin owned by Korean electronics giant Samsung Electronics, according to people familiar with the operation. One of the few major components to be sourced from within the United States, the A5 processor is built by Samsung in a newly constructed $3.6 billion non-memory chip production line that reached full production in early December.

The report also noted that Samsung started supplying Apple with A5 chips from the plant earlier in the year, but just hit full production this month. In September, there were reports claiming that Apple was moving to Taiwan Semiconductor Manufacturing Company for manufacturing of the next-gen A6 chip. That was followed up by reports in October claiming that Apple was indeed ramping up production of A6 chips in Samsung’s Texas plant.

Apple and Samsung have declined to comment.