Granola is a software service that quietly runs in the background and makes use of the hardware-based energy saving feature, Dynamic Voltage Frequency Scaling. Granola idles down your processor to the level that’s appropriate for your usage. I’ve had it running for a week now and have noticed no problems in regards to performance but it tells me it’ll save me quite a bit of energy, money, carbon dioxide output.
The trick to Granola is that your hardware has to support DVFS. Unfortunately, I found that only 1 out of 4 different model computers I tested offered this feature. It’s commonly referred to in its marketing names as AMD Cool-n-Quiet or Intel SpeedStep. You’ll need to enable either of these features (it depends on what processor you have and if your motherboard supports it) in the BIOS. Fortunately, there is a Granola wiki that can provide some direction toward correctly configuring your computer. Once you have that setting configured, using Granola is a cake walk and it runs on Windows 7, Vista, and XP. There is also a means of installing Granola on Linux.
Once you get Granola up and running, it’ll give you a splash screen that can be configured to show you how much it predicts to save annually or show how much you have saved cumulatively.
There isn’t a whole lot to the configuration of Granola, but you can change a few things to suit your needs. You can really crank down the CPU usage for maximum energy savings or the extreme in the other direction or keep it right in the middle for a good balance. You can also change how the reporting looks so it is a little more localized for you if you’d prefer kilograms of pounds and such.
With this kind of simplicity and energy saving as a direct result, I don’t see why you shouldn’t be running Granola if your hardware supports it. Look into it and you might find an easy way to save $25.