The efficiency of mobile processors is a big concern for Apple, particularly with its iPhone and iPod products where battery life is critical. Though Intel has been actively courting Apple with its new low-power Atom chip for use in a number of products – namely the iPhone – the Cupertino-based company pulled a surprise move yesterday by announcing the acquisition of PA Semi, a microprocessor design company best known for its power-efficient 64-bit multi-core processors which are based on PowerPC Architecture.

Apple has declined to comment on their purposes and plans, though there’s a slew of speculation about the motives for this takeover – of course, with the iPhone being one of the main topics. Financial details were not disclosed, but this Forbes story quotes a “person familiar with the deal” who puts the price at $278 million in cash.