Melanie Pinola:

Sleek silver Ultrabooks arriving from major PC manufacturers aren’t just Apple Macbook Air clones. Some of them even have options that Apple’s laptop doesn’t offer.

She goes on to point out the most minute details that make Ultrabooks different from a MacBook Air. Then, somehow we come to the assertion that Ultrabooks have to run Windows.

Even though some laptops do look exactly like the MacBook Air, often there are significant differences inside. Besides running Windows, using Intel processors, and meeting the thinness requirement, laptop makers are free to adapt Intelā€™s specifications for Ultrabooks as they see fit.

I was curious about that so I did a quick search on Wikipedia and found the requirements. It doesn’t appear as though Windows is required. As for adapting the specs how they see fit, I put together a comparison on the Verge. Other than the fact that we’re in the middle of a transition from Sandy Bridge to Ivy Bridge, none of them really stand out from a MacBook Air.