ENERGY STAR® is the government-backed symbol for energy efficiency, providing simple, credible, and unbiased information that consumers and businesses rely on to make well-informed decisions. ENERGY STAR is the simple choice for energy efficiency, making it easy for consumers and businesses to purchase products that save them money and protect the environment. ENERGY STAR Lenovo ThinkCentre M77, 2.8 GHz, AMD Phenom II X2, 4 GB, 500 GB, DVD-ROM, Windows 7 Professional Lenovo ThinkCentre M77. Processor frequency: 2.8 GHz, Processor family: AMD Phenom II X2, Processor model: B53. Internal memory: 4 GB, Internal memory type: DDR3-SDRAM, Memory clock speed: 1333 MHz. Total storage capacity: 500 GB, Optical drive type: DVD-ROM. On-board graphics card model: AMD Radeon HD 4250. Operating system installed: Windows 7 Professional, Operating system architecture: 64-bit. Power supply: 280 W. Chassis type: Tower. Product type: PC. Product color: Black