AMD stock, which climbed nearly 6 percent Wednesday, added another 50 cents, or 7 percent, to $7.69 Thursday afternoon. Shares have ranged from $5.31 to $16.19 over the past year. AMD's new offering, based on its Turion processors and related chipset, is seen as an overhaul of the company's mobile chip lineup which could help fuel a recovery at the beleaguered chip maker.