Windows 8 is built to be power efficient at every point across all devices; Microsoft talks about the measures that they have taken to ensure this in a blog post made on the Building Windows 8 Blog on MSDN.
Are you getting the error message “Consider replacing your battery
” in Windows 7 too often? Microsoft is already looking into the battery issues with Windows 7 and will soon provide a solution for the problem. In the meantime, you might want to try this temporary fix that will disable the error message.