Lenovo ThinkCentre S51 P4 540 3.2GHz, 3.2 GHz, Intel® Pentium® 4, 0.5 GB, 40 GB, CD-ROM, Windows XP Professional Lenovo ThinkCentre S51 P4 540 3.2GHz. Processor frequency: 3.2 GHz, Processor family: Intel® Pentium® 4. Internal memory: 0.5 GB, Internal memory type: DDR-SDRAM. Total storage capacity: 40 GB, Optical drive type: CD-ROM. Discrete graphics card model: Intel® GMA 900. Operating system installed: Windows XP Professional. Power supply: 225 W. Chassis type: SFF. Product type: PC. Weight: 18.7 lbs (8.5 kg)