Here are a few of the dozens of Ultrabook models currently available at different screen sizes.
[Note: Price ranges are from Bestbuy.com and reflect different hardware configurations.]
• Samsung Series 9 ($1,400-$1,800)
• Acer Aspire ($780-$830)
• Vizio Thin + Light ($950-$1,250)
• HP Envy ($680-$770)
• Dell XPS ($650-$1,300)
• Asus Zenbook ($900-$1,500)
• Sony VAIO ($800-$1,200)
• Toshiba Portégé ($760-$900)
12-inch or smaller
• Asus Zenbook ($940-$1,200)
In 2008, Apple launched the MacBook Air, a sleek computer it billed as "the world's thinnest" with a tapered design that ended in a razor-like 0.18-inch edge. Side by side, it made other laptops look positively chunky.
Four years and six revisions later, Apple now faces stiff competition as PCs have slimmed down to compete in the ultra-thin, ultra-portable class the Air established.
In June 2011, Intel Corp. introduced its trademarked Ultrabook brand of laptops that met specific requirements for portability and weight. That August, Intel Capital announced a $300 million Ultrabook Fund to drive development of Ultrabook-class devices, according to a company news release.
This April, Intel CEO Paul Otellini said manufacturers were developing more than 100 Ultrabooks, many of which now are available. This influx of new devices could greatly reduce the MacBook Air's dominance of the ultra-portable market, said Brian Marshall, an analyst with International Strategy & Investment.
Last December, Marshall predicted Apple would sell more MacBook Airs in the coming years, but competing ultra-portable devices would lower its market share from 89 percent in 2011 to an estimated 32 percent in 2012.
But how is an Ultrabook different from a regular laptop? Here's a guide to distinguish the two classes of devices.
• Laptops: Measured diagonally, laptop screens range from 14.4 inches to -- in rare instances -- more than 20 inches. High-definition resolutions tend to run from the equivalent of 720p to 1080p or higher.
• Ultrabooks: Most Ultrabook screens measure 11.6 inches to 14.4 inches diagonally, with a growing number of 15-inch exceptions. Most display at 720p with a handful of 1080p models.
• Laptops: Because of their larger screens and additional internal components, laptops tend to be heavier than their Ultrabook siblings. Most weigh from 5 to 9 pounds.
• Ultrabooks: Ultrabooks are computing featherweights. They use a unibody design, trim unnecessary components and use lighter materials (such as carbon fiber or aluminum instead of plastic) to reduce weight to 2 to 4.5 pounds.
• Laptops: Although not universal, higher-end laptops often are equipped with dedicated graphics cards. These make them suitable for demanding applications such as gaming or photo and video editing. Lower-end devices usually make do with less-powerful integrated graphics cards.
• Ultrabooks: Most Ultrabooks use integrated graphics chips that balance longer battery life with power for low-intensity applications such as Web browsing or streaming video. However, some companies have recently announced they have Ultrabook models in the pipeline with discrete graphics cards.
• Laptops: The variety of laptop configurations run from budget systems using low-end, dated processors to desktop replacements equipped with top-of-the-line, quad-core processors similar to those in high-end desktop PCs.
• Ultrabooks: As an Intel trademark, a device must use one of the company's processors to be called an Ultrabook. Most models use low-voltage versions of Intel's third-generation "Ivy Bridge" processors to reduce power consumption and extend battery life.
• Laptops: Lower-end laptops can be equipped with as little as 2 gigabytes of memory. Midrange devices typically average 4-8 gigabytes, and top-of-the-line systems come with up to 16 gigabytes. Users can upgrade memory on most devices.
• Ultrabooks: Most Ultrabooks come equipped with at least 4 gigabytes of memory. Currently, no Ultrabook is available with more than 8 gigabytes. Many existing models do not let users access and upgrade memory.
• Laptops: Except for high-end systems, most laptops are equipped with hard disk drives that must physically spin in order to access files. Although slower, these drives are inexpensive and offer storage between 250 and 1,000 gigabytes.
• Ultrabooks: Like tablet PCs, most Ultrabooks use solid-state drives, either for primary storage or to improve access to frequently used files. These offer high performance and energy efficiency but also are more expensive and have a smaller storage capacity of 64-256 gigabytes.
OPTICAL MEDIA DRIVE
• Laptops: With the exception of the most recent version of Apple's MacBook Pro, almost all laptops come equipped with a drive to read and/or write to CDs, DVDs or Blu-ray discs.
• Ultrabooks: As a space- and weight-saving measure, Ultrabooks do not feature disc drives, forcing users instead to download software or purchase an external disc drive.
• Laptops: Midrange laptops typically cost $500 to $900. However, the wide range of hardware configurations runs the gamut from $250 budget systems to custom-built, desktop replacements in excess of $5,000.
• Ultrabooks: Because they use higher-end components, current Ultrabook models tend to be more expensive than laptops. Prices range from $650 to $1,800, depending on hardware configuration.
WHAT TO BUY
• Purchase a laptop if you have basic computing needs and are on a budget or need top-of-the-line components for applications such as gaming or video editing.
Despite carrying a comparable price to high-end laptops, many Ultrabooks are equipped similarly to midrange laptops. If you need more or less power and don't plan to take your system everywhere with you, look to the wide range of laptops for a more suitably configured system.
• Purchase an Ultrabook if you want a moderately powerful computer that features modern styling, has a long battery life and is light enough to slip into a bag without weighing you down.
Solid state hard drives and low voltage processors give Ultrabooks a long battery life. This makes them an ideal upgrade for those with touchscreen tablets looking to upgrade to a more capable device without sacrificing portability and weight.