A new survey from the Uptime Institute suggests fatigue is setting in when it comes to making data centers greener, and it may be partly due to overachievers like Google and Microsoft. In the Institute's latest survey of data center operators, only 50 percent of respondents in North America said they considered energy efficiency to be very important to their companies. That was down from 52 percent last year and 58 percent in 2011, and is despite a constant drumbeat of encouragement to reduce energy costs and cut carbon emissions.