Because, microsoft's work is entirely built around the current x86 architecture, windows isnt ported to run on anything but that with the exception of windows CE.They still havent even gotten serious about the 64 bit changes.I think we are witnessing the beginning of the end of the windows life cycle, hardware and other software makers are in a good position to jump on the new technology while microsoft isnt, all its plans involve x86 hardware.Like it or not, hardware and software is tied together, they feed off each other, IBM has gathered together some pretty big names with this upcoming cell processor technology, and theyve sold off their PC division to lenovo, and embraced an OS that can easily make cell processor tech work.From what I know about RISC architecture, its probably a better choice in multiprocessing to begin with, and IBM already has a head start with several years with the PPC chips.They may not make major headway in the desktop market in the beginning, but they will dominate the home media centers,small devices, and still hold onto their huge share of the server market.