Originally posted by: mamisano
Well, I am not sure how accurate the original information is. Here is what is listed on the XP-64 Trial download page: 
http://www.microsoft.com/windowsxp/64bit/evaluation/trial.mspx
System requirements
    * Supported processors: AMD Athlon 64, AMD Opteron, Intel Xeon with Intel EM64T support, Intel Pentium 4 with Intel EM64T support
    * 256 MB RAM
    * 1.5 GB available hard-disk space
    * Super VGA (800x600) or higher resolution video card
    * CD-ROM or DVD drive
    * Keyboard and Microsoft Mouse or compatible pointing device