We've seen it put its processing power behind the iPad 2 and heard rumors of its presence in the upcoming fifth-gen iPhone, but could Apple really be considering putting its mobile-minded A5 processor in a MacBook Air? According to Japanese website, Macotakara, a trial of the ARM chip is already underway. Apple's reportedly been experimenting with a Thunderbolt-equipped MacBook Air with the A5 on board, and "according to someone who has seen a model running with [Apple's] A5 processor, the performance is better than had been thought." Two weeks ago, we reported on rumors that the upcoming MacBook Air refresh could be on its way as early as next month, featuring Intel's Sandy Bridge 17W mobile processors -- a claim we'd say could hold water. Of course, this information has trickled a ways down the grapevine, and the presence of an A5-packing test vehicle doesn't mean much anyway, but you can consider our interest piqued, regardless.