PowerSave: A Tale of Two Products


In Love With the Kindle Paperwhite


The 6th Generation Kindle Paperwhite Available on Amazon.in


Which eBook Reader for Your Tour?


Kindle Paperwhite, Kindle Fire HD 7” and Kindle Fire HD 8.9” available for purchase on Amazon.in...

I'm using two of several products launched in October. Windows 7, and Amazon's Kindle 2 e-book reader, global edition. Both get a special mention in this column on green tech.

You know by now that W7 is superior to its predecessor... of course. The less said about Vista... W7 is faster. It installs quickly, starts and shuts snappily, even loads apps faster. What surprised us, in our tests featured last month, was performance on an old P4 PC with 1 GB memory. W7 ran faster than not just Vista, but also faster than XP and two Linux strains.

Good software can also reduce power draw. Writing this on a ThinkPad T400 running W7, I notice that it uses the hard disk less. Other than quicker startup and shutdown, there's less memory (and thus swapfile and disk) use...and less CPU use. That translates into longer battery life. While I did not check this out against Vista, a Microsoft-Intel test (http://bit.ly/W7-batt) on T400 laptops shows the W7 laptop drawing 15.6W, with 20% better battery life than the Vista one (20.5W), playing a DVD movie-5.46 hours on W7 versus 4.14 hours on Vista.

W7 smartly puts to sleep parts that aren't needed: a second CPU core, a hard drive, USB ports, even Wi-Fi when you're not connected to a network. The system timer's been tuned, and it also doesn't wake up an idle CPU unnecessarily, reducing power draw further. W7 also lets developers more easily use resources including the CPU on-demand, rather than running all processes all the time in the background.

In its default setup, W7 may not be great on power efficiency. All those smooth Aero and graphics effects draw power, use memory, and, together with multiple apps loaded, can increase hard disk activity. Optimizing power and extending battery life may need tuning: turn off Aero, minimize multiple loaded apps when on battery, ensure your hard disk's de-fragged, and add RAM-2 GB works better than 1. More on this after other tests in our labs.

On the Amazon Kindle, I'm midway through Dan Brown's Lost Symbol. The Kindle is a quite delight, and it takes less than one book to get used to e-book readers. But the real remarkable thing about it-and about other e-book readers too-is power efficiency.

Battery life has to be a top feature on an e-book reader. You don't want to be racing with the battery to finish a book, something you'd be doing if you were using a PC or tablet with a five-hour battery.

So a big step for the e-book reader was e-ink, or e-paper. This display is not backlit, but reflects light, rather like ordinary paper, so you can read it outdoor too. It requires a little power only to update the display-and then it stops drawing power.

So the Kindle runs for up to 14 days on a charge, with its wireless off. I charged it for an hour out of the box and have now used it for five days so far, with a bit of wireless use to download a book or two, and find the battery's still showing nearly full.

The e-book reader is a great example of what advances in low power devices and battery life can allow. Without the e-paper display and the long-life battery, the Kindle and its ink would not have been possible.

The author is chief editor at CyberMedia, publisher of 15 specialty titles including PCQuest.
You can reach him at pkr@cybermedia.co.in, twitter.com/prasanto.

  • Follow PCQuest on
  • become a fan on
  • Stay updated via
  • RSS


Notify me of follow-up comments via e-mail address

Post Comment

Survey Box

Now that Microsoft has finally discontinued support for Windows XP, which OS are you likely to upgrade to?

Send this article by email