Three-year Growth: 293.9%
2004 Revenue:$112.4 million
No. of Employees: 504
Founded: 1996

What it does: Custom-builds supercharged personal computers--mostly for hard-core computer gamers. Why it's growing: Computer gaming is an $11 billion-a-year industry and growing fast. Alienware machines, which cost as much as $30,000, are equipped with super-fast graphics processing and high-performance screens and sound systems.