Test Battery Life and Power Consumption
Compare the overall system power to the power that the system consumes when you use a clean installation. With preinstalled applications and power policies, some computers have shown a 40 percent decrease in battery performance compared with a clean Windows® installation. However, through careful engineering, computers can achieve equal or improved performance over a clean Windows installation.
Determining the causes of heavy battery use
You can determine the causes of heavy battery use by looking at the way that the system uses resources. You can find many system problems by looking at processor idle time. Use a performance tool, such as Windows Assessments or the Windows Performance Toolkit, to investigate when the system has spikes in power use. Performance tools can help you target the applications that are causing increased processor use.