With Windows Vista, customers are free to choose either 32-bit or 64-bit editions when purchasing Windows-based computers, and licenses for Windows Vista are valid for both 32-bit or 64-bit editions of the OS. Because 圆4 editions require a new generation of 64-bit native drivers, this first release was limited to OEM distribution. Windows XP Professional 圆4 Edition introduced the OS enabling technology for 圆4 released in April of 2005. The majority of new CPUs sold in the past few years, and almost all processor lines in development from AMD and Intel, are 圆4-capable. 圆4 technology is widely available in the market.
