read what M$ said:

for Windows XP Professinal:
PC with 300 megahertz or higher processor clock speed recommended; 233 MHz minimum required (single or dual processor system);* Intel Pentium/Celeron family, or AMD K6/Athlon/Duron family, or compatible processor recommended
128 megabytes (MB) of RAM or higher recommended (64 MB minimum supported; may limit performance and some features)
1.5 gigabytes (GB) of available hard disk space*
Super VGA (800 × 600) or higher-resolution video adapter and monitor