It looks like Acer may be dropping down to the lightweight laptop division, now that images of its so-called Aspire 3951 have leaked out of Vietnam. An ostensible rival to the recently refreshed MacBook Air, the 13.3-inch 3951 reportedly boasts a similarly slim design, measuring 13mm thick and weighing less than 1.4 kilograms (about three pounds). According to Sohoa, the aluminum-cased device is powered by a second generation Intel Core processor, features an optional 1