Lenovo ThinkCentre A51, 1.73 GHz, Intel® Pentium® 4, 0.5 GB, 80 GB, DVD-ROM, Windows XP Professional Lenovo ThinkCentre A51. Processor frequency: 1.73 GHz, Processor family: Intel® Pentium® 4, Processor model: 530. Internal memory: 0.5 GB, Internal memory type: DDR2-SDRAM. Total storage capacity: 80 GB, Optical drive type: DVD-ROM. Discrete graphics card model: Intel® GMA 900. Operating system installed: Windows XP Professional. Power supply: 310 W. Product type: PC https://www.pcmag.com/review/169443/lenovo-thinkcentre-a51-ultra-small-8105-26u The Lenovo ThinkCentre A51 Ultra Small ($1,299 direct, $899 without monitor) is a secure small form factor business desktop suited for both the small office and for enterprises. Unlike older small-sized systems, such as the Apple Mac mini), which hav... Compact. Shares Ultrabay components (optical and removable hard drives) with ThinkPad line. Hardware security, including biometrics. Easy-to-service components. Internal power supply. Not very expandable. Non-removable palm rest in keyboard. With a compact form factor, decent pricing, and proven quality, the Lenovo ThinkCentre A51 Ultra Small should easily find a home in offices around the country.... Well-designed office PC takes up little space and permits easy--though limited--upgrades to extend its useful life. Small footprint; well designed Modest performer; limited expandability Adequate expandability will keep this small-footprint PC on office desktops well into the future.