Putting a 'Dimmer Switch' on PCs can Cut Energy Use by 30 Percent

Putting a 'Dimmer Switch' on PCs can Cut Energy Use by 30 Percent

Somewhere between awake and asleep (and drowsy) lies ... Granola.

That's the improbable name of a free software program, launched in January but undergoing a big education push tied to Earth Day, that aims to cut the energy wasted by computers in a significant way.

The program, which works on x86 platforms for servers, desktops and laptops that are running Windows or Linux, matches the computing demands of system with the energy used, and its creators say Granola can cut energy use by 30 percent without affecting performance.

Granola saves energy by applying dynamic voltage and frequency scaling (DVFS) to the CPU of a system, something the company shorthands as akin to a "dimmer switch." When a user is reading a website or working in a word processor, Granola scales down the power needed; when the CPU is running at full blast for creating charts and graphs or other computing-intensive processes, the software draws more power. The chart below, courtesy of Granola's benchmarking information, shows how the software affects power used with Excel running.

This is where Granola's creators, MiserWare say the software gives them an edge. By not relying on policy-based downtimes or periods of inactivity, Granola can bring steady energy savings to PC fleets.

The company, which is a spinoff from Virginia Tech, says that the energy and greenhouse gas emissions savings from widespread use of Granola could be huge: Using the pie-in-the-sky figure of installations of Granola on 1 billion personal computers around the world, MiserWare estimates savings equivalent to taking 7 million cars off the road, or planting 900 million trees.

There are any number of software programs that aim to help companies and individuals reduce the energy demands of their PC fleets. A PC Power Management Summit convened last year by the EPA highlighted some of the basics of how to get started, and what kinds of benefits are available from installing power management software.

More information and free downloading of the software is online at http://grano.la.