Tech stocks started Tuesday on a climb, but then retreated into the red following testimony by Federal Reserve Chairman Ben Bernanke that further shook investor confidence. The Nasdaq was down 61 points, or 3.3%, to 1802 in recent trading. AMD ( AMD) shares shot up after the chipmaker confirmed plans to spin off its manufacturing operations into a new joint venture with an Abu Dhabi investment firm as a way to cut down on costs. AMD's stock jumped 17.5% to $4.97 on the news. Shares of Google ( GOOG) and Yahoo! ( YHOO) were trading lower after Stifel Nicolaus cut estimates and offered a cautious outlook on both companies. The firm maintained a buy rating on Google but lower its price target to $525 from $600 after noting a "sharp slowdown in business activity" late in the third quarter. For Yahoo!, Stifel Nicolaus left its buy rating and price target of $26 unchanged, but cuts its earnings estimate for the year to 70 cents a share from 78 cents a share. Google was down 4.5% to $354.57, while Yahoo! was down 3.8% to $14.73. SAP ( SAP) shares slid for a second straight day after the Walldorf, Germany-based software maker warned on Monday that sales had dropped off sharply at the end of its third quarter as customers were holding back on their spending. Goldman Sachs chopped its price target to $43 from $56. Shares of VeriSign ( VRSN) were up 2.1% to $24.46 after the company announced the sale of its minority share in a mobile entertainment joint venture to News Corp. ( NWS).