U.S. chipmaker Advanced Micro Devices Inc forecast weaker-than-expected first-quarter revenue and said it taking steps to return its computing and graphics businesses to a "healthy trajectory" from the second quarter. The company also reported lower-than-expected fourth-quarter revenue as it struggles with weak sales of graphic cards and to compete with Intel Corp in a declining PC market. AMD shares were down nearly 1 percent at $2.22 in extended trading.