Let the hardware shine. We built Windows 8 such that the power efficiency of the hardware platform shines through, regardless of whether the system is a SoC-based Windows tablet or an SLI-equipped gaming PC. We designed our power management interfaces in a consistent, standardized way across all platforms. This allows our hardware partners and application developers to focus on their unique innovations and experiences instead of the differences in platform hardware and power management.

     Continue to deliver great battery life. Windows 7 delivered a significant reduction in power consumption and increase in energy efficiency, particularly mobile PC battery life. (In fact, you can read how we thought about it in this e7 blog post.) In Windows 8, we want to maintain that same level of efficiency on existing PCs even as we re-imagine the rest of Windows.

     Enable the smartphone power model. One of the coolest things about the System-on-Chip (SoC) platforms you’ve seen us talk about at CES and //BUILD/ is their capability to quickly enter very low-power idle states. We want to leverage that ultra-low idle power to bring the constant connectivity and instant-on features of the smartphone power model to capable Windows 8 PCs.

Why it matters?

     Most of us are probably familiar with one impact of good power management—long battery life on our mobile devices. Mobile computing devices are highly scrutinized for their battery runtime with good reason—we are using them on battery more often than ever before. Delivering consistently long battery life requires a lot of well-executed coordination between the underlying hardware, operating system, and application software. (Battery capacity and its quality over time also have a big influence on runtime.)

     In addition to mobile battery life, the next most tangible impacts of good PC power management are reduced energy costs and environmental impact. The benefits of power-managing enterprise desktop PCs and servers in the datacenter are typically positioned as reducing the amount of money required to power and cool those systems as well as the resulting reduction in greenhouse gasses required to produce the energy for them. It’s hard to underestimate the impact here—very small changes done well in Windows can result in very large positive environmental impact because of our scale. In many markets around the world, increasing electricity consumption is putting more demand on every aspect of the workplace to reduce power consumption. PCs are a significant source of potential savings.

     Power management is also in a fine balancing act with system performance and responsiveness. As an example, we can easily reduce processor performance to save power, but as we do so, we increase the time required to process a given workload. Doing a great job of balancing power and performance is a key requirement across the Windows user experience.

     We are also observing a lot of tech blogs reviewing the latest processors and hardware platforms, not just on GHz and benchmark performance, but also on the power consumed to execute the workload. These measurements combine power and performance into energy efficiency—how much power does it cost to execute some fixed workload. “Performance per watt” is the same thing.

     However, the thing that excites us the most is how power management is fundamental to all aspects of PC platform design. Power management directly impacts attributes including thickness, weight, acoustics (fans and their speed), skin temperature, cost, screen size, resolution, RAM quantity, etc. Hardware that is thin, light, always connected, and runs all day on battery is cool. We love being a part of enabling that for the Windows ecosystem.