Microsoft is expecting Windows Server 2008 systems to use about 20 percent less power than existing Windows Server systems, ZDNet reports.

“We’ve done power management by default in Longhorn Server,” said Windows Server General Manager Bill Laing. “And we think average machines will see maybe 20 percent reduction in power use. You kind of slow the clock down when it’s not busy.”

Also, according to the article, it looks like Microsoft is also working on an official “Green Datacenter Strategy.”

Microsoft recently faced criticism from environmental organizations who said Vista could lead to a mass upgrade of PCs that would result in old machines being dumped in landfills.