Several Websites report that Windows XP 64-bit has reached gold status and is on the way to the CD manufacturer. MSDN subscribers can already download the final release of Windows XP 64-Bit Edition. The top 5 reasons to upgrade are (from MS Website): High performance platform for the next generation of applications: Windows XP Professional x64 Edition is a rich platform that enables the next generation of high-performance computing. 64-bit native applications can deliver more data per clock cycle, making them run faster and more efficiently. Large memory support: Windows XP Professional x64 Edition will currently support up to 128 gigabytes (GB) of RAM and 16 terabytes of virtual memory, enabling applications to run faster when working with large data sets. Applications can preload substantially more data into virtual memory, allowing rapid access by the 64-bit processor. Flexibility: Windows XP Professional x64 Edition provides a rich platform to integrate 64-bit technical applications and existing 32-bit business applications using the Windows on Windows 64 (WOW64) x86 emulation layer, providing customers with the ability to move to 64-bit computing without having to sacrifice their existing investment in 32-bit software and Windows expertise. Multiprocessing and multicore: Windows XP Professional x64 Edition is designed to support up to two single or multicore x64 processors for maximum performance and scalability. Same programming model: Developers with 32-bit skills will be comfortable and quickly productive in the 64-bit Windows environment, finding it virtually identical to the development environment for 32-bit Windows. I have seen many reviews which compare 64-bit vs. 32-bit and there is not much gain to see, unless you use specialized applications.