Intel (INTC -1.7%), AMD (AMD -2.9%), Dell (DELL -1.9%), and H-P (HPQ -2.2%) underperform after Evercore's Rob Chira slashes his estimates on (what else?) concerns about PC demand. Chira now predicts 2012 PC unit sales will fall 4% Y/Y, worse than IDC's forecast, and expects flat sales next year. "We estimate Q3 units fall year-over-year across every major market: Consumer, corporate, desktop, notebook, U.S., Europe, and APAC," he writes. AMD is also getting hit by an estimate cut from JMP.