SAN FRANCISCO (Reuters) - Personal computer makers are increasingly prioritizing "green" strategies, creating a pivotal point of competition for customers that are becoming more attuned to their financial -- and societal -- benefits.

Analysts say going green has become a business plan unto itself for the industry's heavyweights: a way to stand apart from rivals, win over a growing segment of environmentally conscious consumers, and shore up branding worldwide.

The three major U.S. computer vendors -- Hewlett-Packard Co, Dell Inc, and Apple Inc -- argue that customers glean real benefits, for example lower power consumption in green-certified display screens.

"It's really a green arms race, in which they're trying to one up each other," said John Spooner, an analyst with Technology Business Research. "The good news is they're all working in this direction and that's going to benefit themselves, their customers and the environment."

Analysts point to certain efforts -- such as Dell's recycling program, Apple's moves to remove toxic raw materials, and HP's actions around packaging -- as areas of success.

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But the IT industry still accounts for an estimated 2 percent of global emissions of greenhouse gas carbon dioxide.

Consumers might have trouble picking out just who among the PC makers are making the right moves: Dell says it aims to become the "greenest technology company on Earth"; Apple lays claims to the "greenest family of notebooks"; and HP stresses it has a long tradition of environmentalism as well as the market size to effect change.

TBR recently ranked Dell No. 1 out of 40 technology companies on corporate sustainability. But a recent Greenpeace report ranked Apple best among the major PC makers.

While there are differences between the three in areas such as materials, PC power usage and recycling and packaging, analysts and environmental groups say, the green agenda is profiting from the competition between them.

Campaigns by interest groups like Greenpeace to praise or tweak PC makers have been particularly effective.

"Companies are realizing that consumers do use these environmental considerations as tiebreakers. It does help differentiate their products," Forrester's Sally Cohen said.

Around 70 percent of companies surveyed in a recent report by Forrester Research cited product differentiation -- the desire to stand out -- as a business driver for their environmental strategies.

"It has struck a chord with consumers, businesses, stakeholders and NGOs," said Eric Lowitt, a research fellow at Accenture.

In interviews, Dell and HP -- while each asserting leadership -- downplayed talk of competition. They pointed out that any good sustainability strategy must be comprehensive, and span the company, right down to its supply chain.

Some analysts say what may be more important than companies' actual green initiatives -- often highly technical -- is their ability to communicate them to the market.

Tod Arbogast, Dell's director of sustainable business, said there is actually some collaboration around green initiatives.

"I don't think we've reached the tipping point yet, I think we'll continue as an industry to innovate, challenge one another to go further. faster on these efforts," he said.

Bonnie Nixon, HP's director of sustainability, said green practices should be integrated throughout the company.

HP's "commitment has really been there, certainly through the 90's and the fact that society is really focusing on green right now is great. We're in an industry that can truly demonstrate" environmental leadership, she said.

(Editing by Edwin Chan and Tiffany Wu)