Source -With the advent of Microsoft’s Windows 7 and Windows Server 2008 R2 operating systems, the company also applauded its most green platforms to date. Over three months after the general availability of Windows 7, the Redmond company revealed that Stephen Berard, a senior program manager for the Windows Kernel Team, was the man that helmed efforts to make the OS as energy-efficient as possible. Berard was also the recipient of Microsoft's quarterly Environmental Action Award, for the features built into Windows Server 2008 R2 which contributed to servers becoming more energy efficient. According to Berard, Windows Server 2008 R2 is the more efficient and more manageable Windows OS ever produced by Microsoft.
Behind Windows 7?s Energy-Efficiency Boost - Stephen Berard, a senior program manager for the Windows Kernel Team - Softpedia