Lenovo on Monday launched the much-anticipated ThinkPad X300 ultraportable, challenging Apple's MacBook Air as the lightest notebook available today.

With a starting weight of 2.93 pounds, the ThinkPad X300 is more feature-rich, Lenovo claims, than Apple's 3-pound MacBook Air. Lenovo has included three USB ports and an ultrathin DVD burner, while MacBook Air has only one USB port and no optical drive. With a DVD-RW drive, the X300 weighs 3.13 pounds, Lenovo said.

[ Read InfoWorld's hands-on review of the MacBook Air ]

The laptop measures 0.73 inch at its thinnest point and 0.92 inch at its thickest point. That's larger than the MacBook Air, which measures 0.16 inch at its thinnest part and 0.76 inch at its thickest part.

Targeted at business users and consumers, the Lenovo laptop uses 25 percent less power than previous ThinkPad models, with a 64GB solid-state storage drive for data storage, a 13.3-inch LED-backlit display, and use of a lithium-polymer battery, Lenovo said.

The lithium-polymer chemistry provides better battery life than standard lithium-ion batteries found in most laptops today, said Tom Ribble, director of ThinkPad product marketing at Lenovo. The system supports up to 4GB of memory and includes integrated graphics, a digital camera, and wired and wireless networking. It includes both touchpad and trackpoint scrolling capabilities.

The system will come with WiMax capabilities later this year with Intel's updated Centrino platform, according to Lenovo. The buyer may choose that the machine come preloaded either with Windows XP Professional or Windows Vista.

The X300 is powered by Intel's Core 2 Duo SL7100 LV low-voltage chip, operating at 1.2GHz. Like the Core 2 Duo processor specially developed for Apple's MacBook Air, Intel shrunk the SL7100 LV processor to make it 60 percent smaller than standard-sized processors belonging to Intel's Merom family. The chip is manufactured using the 65-nanometer process, like other Merom processors.

Although the size is the same as other Merom processors, the SL7100 LV chip consumes less power. It uses 12 watts of power, according to processor details provided by Intel. The Core 2 Duo processor for MacBook Air uses 20 watts of power, while operating at 1.6GHz to 1.8GHz. Fujitsu also uses the SL7100 LV chip in its ultraportable LifeBook P8010 laptop, which started shipping in the United States this month.

Lenovo has pumped the latest technology into its laptop that both consumers and business users will appreciate, Ribble said.

Prices for the X300 start at $2,799, and it is available through Lenovo's Web site and through retail partners. It was not yet listed on Lenovo's Web site at the time of the announcement.