Talk about the battery life running Vista is not going away but finally Microsoft has weighed in on the issue on the Windows Vista Team Blog. Vista product manager Nick White, whom I’ve had the pleasure of meeting several times (really nice guy) has posted a response to Dwight Silverman’s post on the issue. We linked to Dwight’s post way back when and Nick has responded directly to that post. Long and short of it Nick says what we already suspected, that Aero Glass works the GPU harder and consumes more power as a result. Here’s the take from Nick:
First off, yes, as Dwight correctly points out, the Aero theme drives the GPU harder and therefore uses more power. But in the big picture, it’s really not that much more. For example, the display on most laptops will consume somewhere between 15-25% of your "power budget" when you are running on battery. Nevertheless, in our testing we’ve seen that turning on Aero consumes only about 1-4% more of battery life. In terms of making your battery last longer, turning off Aero will not go very far while at the same time costing you some of the cool features that make Windows Vista fun to use, such as Flip 3D, taskbar previews, window transparency and so on.
Further, as Dwight correctly points out, your mileage can vary widely depending on the workload the machine is running (he uses the example of playing Doom3.) To use an Aero-specific example, you would use more power enabling transparent window borders and stacking a lot of windows upon a portion of the screen showing a video clip. The GPU would be required to constantly re-render those parts of the screen that make up the transparent window edges, which in turn drives the GPU harder.
Now, we know there are times when you want to fully maximize battery life and every little bit helps. It’s for this reason that we automatically turn off things like window transparency when the machine is put into a power-saving profile. We don’t turn off Aero wholesale because in the end, doing so is not going to save you much more power. So we turn off the transparency effects and maintain a smooth user experience. We know that it results in a tradeoff, but we also think it’s a fair one to make.
What is not clear is why some UMPCs that can’t run Aero Glass also show a battery life decrease. There’s no GPU on devices with integrated graphics either and a lot of those owners are grousing about poor battery life.