Not so green computing: Is Windows an energy hog?

Many data centers are looking for energy efficient hardware. Mallory Forbes thinks they should be looking at the software too - and Windows in particular.

"Quite often you see applications that require a heck of a lot of horsepower to get them to run well. To get the response times... you end up buying a fairly significant number of devices or very large devices to make them run," says Forbes, senior vice president and manager of mainframe technology at Regions Financial Corp. in Birmingham, AL. Much of the time, those inefficient applications are running on top of Windows, he claims.

As the performance of hardware continues to go up and prices continue to drop, there's been little pressure on software vendors to write efficient code, he says. If anything, that code has been getting bigger and more bloated over time. Now that spiking power requirements and heat density issues have IT's attention, he thinks it's time to revisit the issue of software efficiency.

Case in point: The Windows operating system and the applications designed to run on it. "On the whole, Windows platforms are less efficient" than applications running on Unix, he says. Forbes says that as the bank prepares to consolidate servers onto virtual machines it has been performing studies of hardware utilization levels for applications running on both Unix and Windows servers. "The utilization rates for our Windows boxes are dramatically lower than for our Unix boxes," he says. The bank uses Linux, AIX and Solaris, which he says are more efficient. "If we can put something on Unix we prefer to do that," he says.

Amory Lovins, CEO at energy efficiency think tank Rocky Mountain Institute also suspects there's significant energy savings to be had from using more efficient software. "I would be very interested to see comparisons [between] applications or at least [benchmarks that] perform a comparable task under different operating systems with the same hardware," he says. In this way, the user could find out exactly how many processor cycles - and how many watt-hours of power over time - are required to get the same amount of work done. "It's a rich field for exploration, but I don't have a good data and I don't know if anyone does," he admits.

I haven't seen any studies relating software efficiency (or lack thereof) to energy efficiency. From your experience, do you buy the argument that the applications and operating system can substantially affect overall energy efficiency of the systems in a data center?

Could an operating system such as Windows, and the applications running on top of it  - be an energy hog?