The improvement you’ll notice the most with Windows 8 is in battery life. What’s impressive is that not only will your notebook PC run for longer with Windows 8 on than with Windows 7,but it does that without reducing performance.
Our test PC is a business ultraportable from 2010 (the HP 2740p UltraBook) with a six-cell 44Wh battery that’s always had slightly disappointing battery life, especially on Wi-Fi. Upgrading to Windows 8 made the two year old battery perform better than it did when the PC was new. We timed battery life in normal use, with a mix of editing documents, reading Web pages, playing games, editing photos and streaming videos – all on the desktop rather than in Metro applications, for a fair comparison with Windows 7.
The timings in the chart show battery life with Wi-Fi on and off, and with a USB drive plugged in. that’s important because there are two main ways that Windows 8 saves power. The first is by taking all the different things that wake the processor up in the minutes while you’re not doing anything power intensive – reading a Web page you’ve already loaded rather than following a link, for example – and doing them at the same time. That means the system can drop into a lower power state for longer, because it doesn’t get woken up as often.
The second thing is aggressively turning off devices and ports when you’re not using them. This is down to drivers and devices supporting the new power management features so it works best with new devices. Leave an SD card or USB stick plugged into a Windows 7 PC and it uses a little more power. Leave it plugged in with a Windows 8 system and the difference is more noticeable. Without a USB stick plugged into the PC, the battery life in Windows 8 was 30 minutes or an hour longer in some tests. Unplugging what you don’t need makes much more of a difference in Windows 8.
Better battery life in Windows 8 is good news for new PCs as well as for making your current laptop last longer. New PCs can be thinner, lighter and quieter and still have the same battery life as PCs today, or they can have the same size of battery but use that to drive a larger screen or more memory and get the same battery life – or they can be the same size as today’s PCs and run for a couple of hours longer.