Apple on Tuesday announced that it beefed up its iMac all-in-one desktop computers with powerful new-generation Intel chips and high definition cameras.

MacWorld attendees look at a display of iMac computers.

The latest iMac computers were touted as 70 percent faster than their predecessors with a threefold improvement in graphics.

New iMacs were available at Apple stores and the California firm\'s online shop with prices starting at USD1,199 for models with 21.5-inch (546 millimeter) screens and USD1,699 for models with 27-inch (685-millimetre) screens.

"Our customers love the iMac\'s aluminum enclosure, gorgeous display and all-in-one design," said Apple senior vice president of worldwide product marketing Philip Schiller.

"With next generation quad-core processors, powerful new graphics, Thunderbolt technology and a FaceTime HD camera, we\'ve made the world\'s best desktop even better."