Sun allows employees to work from home to cut down on driving, and sold a 1.4 million square-foot office campus in Newark, California, in 2006, eliminating the energy to heat, light and cool it, he said.

Sun is one of the U.S. Environmental Protection Agency's (EPA's) Climate Leaders, a group of 117 companies that have pledged to reduce GHGs. There were only 11 five years ago. Companies share case studies with each other on how they are reaching toward their goals, some reporting a return on investment of 5 percent to 30 percent, said Jim Sullivan, director of the program at the EPA.

Technology vendors can help their customers reach their goals by continuing to create more energy-efficient products, said John Tuccillo, vice president of industry alliances at American Power Conversion Corp. and a member of the Green Grid, a tech industry energy group.

"If our efforts help end users accomplish greater computing throughput for less wattage, the demand put on utilities to maintain a constant computing throughput would be reduced," Tuccillo said.

Heightened concern about climate change has prompted calls for federally mandated limits on greenhouse gases. Some companies acknowledge that taking action now could avoid added regulation later. But AMD's Garcia said companies need to do it because it's the right thing to do.

"If we're doing it for opportunistic reasons, like to get ahead of the curve if the laws change, we're doing it for the wrong reasons," Garcia said. "But, as a practical matter, if you're already thinking that way, then you're in good shape if the laws change."