Test Setup

As stated, we are testing four different operating systems. In order to keep the number of benchmarks manageable, we are focusing on two primary battery life scenarios. Our first test is an Internet web-browsing scenario. We configure the chosen browser to load three websites that contain Flash content every 60 seconds. When the battery level goes critical (usually 1%, although Windows 7 doesn't let us set this lower than 3%) the system shuts down. The second test is DVD playback battery life, again with the system set to run until the battery level is critical. The various operating systems don't necessarily give you the same level of control over power saving features, so we tested a couple scenarios on each Windows OS.

Windows XP

Windows XP gives you the least control over power saving features. We test two scenarios, one using the Portable/Laptop profile and the other using the Max Battery profile. We don't have specific details on what these settings mean in terms of maximum CPU performance, but it's clear that they do affect performance. They also impact battery life, and most people only want enough performance when running on battery life for their system to work properly. We did not experience any difficulties watching DVDs or surfing the Internet, although more CPU intensive tasks may have problems when using the Max Battery profile. On the Portable profile, the HDD is set to power down after five minutes, while the Max Battery profile has it set to power down after three minutes. We also measure LCD brightness with a colorimeter and set it as close to 100 nits as possible.

Windows Vista/7

Similar to Windows XP, we test two different power profiles in Windows Vista and 7: Balanced and Power Saver. These profiles correspond roughly to the same settings as the Windows XP profiles, but this time we have more control over the various details. For Windows Vista and 7, we use the following settings under Balanced.

The hard drive is set to power off after five minutes. The wireless adapter is set to medium power saving, hybrid sleep is enabled, and USB selective suspend is enabled. PCI-E link state power management is set to maximum power saving. The minimum processor state is set to 5% and the maximum processor state is 100%; we don't know how this specifically affects CPU clock speeds, and if you want to run a similar test make sure your notebook manufacturer doesn't specify different values. Search and indexing is set to power saver and adaptive display is disabled. Again, we calibrate the LCD to run at 100 nits, which is 35% brightness for these two laptops (three steps above minimum brightness).

The Power Saver profile uses the same settings in most areas, but we set the hard drive to power down after three minutes, the wireless adapter is at maximum power saving, and the maximum processor state is 50%. Windows 7 does include a few other areas that you can tweak, but most of these relate to LCD dimming in order to conserve power. This is not to say that Vista and Windows 7 are the same, because as we will see in the results there are some definite differences.

Ubuntu 9.0.4 (Jaunty)

There aren't a lot of power saving features available for tweaking within Linux - at least not that I could find. We configured the LCD to never shut off (just like on Windows), and set the system to shut down at 3% battery - the minimum we could specify. We also disabled LCD dimming. Honestly, I don't know nearly as much about Linux as Windows, but I did my best to get Linux installed properly on the two notebooks. As anyone who has used Linux before can tell you, getting driver support is sometimes a real pain in the rear.

Generally speaking, both systems also felt far more sluggish running Linux, especially for typical web browsing. We used Firefox 3.0 initially and then updated to 3.5 - not as easy as I would like under Ubuntu, and I have no idea why the latest build is called Shiretoko in some places and Firefox 3.5 in others. Whatever. Both versions of Firefox felt incredibly slow, but that was with Flash enabled. With the FlashBlock add-on, Internet performance was significantly better, but that isn't a fair comparison to the Windows browser tests. As a point of reference, we ran the same test under Windows Vista and achieved significantly better battery life. We will get to those results in a moment.

Our issues with configuring Ubuntu don't end with the browser, however. On the Intel-based NV58, we could not get LCD brightness to function properly. The result is that the LCD ran at maximum brightness during our tests, which obviously results in lower battery life. We tried to find an updated driver for the Intel GMA 4500MHD graphics, but so far we have been unsuccessful in addressing this issue. The AMD-based NV52 wasn't any better, but for different reasons. We could find updated drivers from ATI, but after repeated attempts we never did get them to function properly. We were left with running the proprietary fglxr 8.600 driver, and while it worked fine in general we had problems with DVD playback. VLC repeatedly crashed during our benchmarks, sometimes after a few minutes, sometimes after 50 minutes. Eventually, we decided to uninstall the proprietary ATI driver and test out the open-source MESA driver. Surprisingly, the open-source driver actually provided a better experience, although we aren't looking at 3D performance where ATI's fglxr driver likely has an advantage.

The short story is that while everything eventually worked out okay on the NV52, the number of headaches we encountered trying to get everything working properly under Ubuntu is more than a little frustrating. You get a sense of accomplishment once everything is working, or at least I did, but that's not something most people are interested in doing. Most people view computers as a tool and they wanted to "just work"; they don't want to scour the Internet looking for instructions on how to manually install the latest drivers/application/whatever. If you're Interested in a more detailed look at Linux, we suggest you read our Ubuntu 8.04 Article. The only area of Linux that we're testing today is battery life.

Index Gateway NV52 (AMD) - Battery Life
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  • Veerappan - Tuesday, September 22, 2009 - link

    I'm not sure if it's possible at this point, but if you can, would it be possible to try out a copy of the 9.10 Alphas that are available? They should hopefully fix some of the intel driver regressions.

    Also, as an FYI/diagnostic, there's a CPU speed applet that is available in Gnome. Right click the top panel, select 'add to panel', and then somewhere there's a cpu speed monitor. That can be used to see if SpeedStep/Cool'n'Quiet are working correctly. You can even take it a step further, and change the permissions of the applet to allow you to change which CPU speed governor is active if you find that the CPU is running at full speed constantly.
    Reply
  • lyeoh - Tuesday, September 22, 2009 - link

    By the way, you should not use external sites during your test. The fact that you said "perhaps a Flash ad server was temporarily down" means you are doing it wrong.

    Different flash ads could be very different in CPU usage.

    What you should do is snapshot/save the complete pages loaded from the websites you want, put them on a standardized webserver under your control, and then get the browsers to load the pages from that webserver. Disconnect the test network from the internet to prove that the page loads up fine without requiring external connections (css etc). You may need to include a test DNS server that fakes the replies, or stick to using IP addresses to access the test pages e.g. http://10.5.5.1/site1/testpage1.html">http://10.5.5.1/site1/testpage1.html http://10.5.5.1/site2/testpage1.html">http://10.5.5.1/site2/testpage1.html http://10.5.5.1/site3/testpage1.html">http://10.5.5.1/site3/testpage1.html

    Once you have standardized on a set of pages, this means you don't have to redo the tests on all computers weeks/months later when you have another laptop to test. You only need to test the new device - since the pages are the same. Don't change the webserver too much either (but given the low loads it's unlikely to affect things much - unless it's really really slow).
    Reply
  • JarredWalton - Tuesday, September 22, 2009 - link

    Already in progress, after my round two Internet testing still proved too variable. As noted elsewhere, though, I want the content to be as close to realistic as possible. Law of averages says that most of the ads will balance out. It's also possible my home wireless phone knocked out my home WiFi a few times, which would mean several minutes (more?) of non-traffic. Many times I'm not around while letting the battery drain, since that's a bit of a waste of time.

    I need a new home phone for sure, though. The 2.4GHz model I bought several years back wreaks havoc on my 802.11n network.
    Reply
  • strikeback03 - Wednesday, September 23, 2009 - link

    You need a home phone at all? Reply
  • JarredWalton - Wednesday, September 23, 2009 - link

    Babysitters might need something to call us, yeah. Could leave a cell with them I suppose, but I also use it for business/fax. Reply
  • 7Enigma - Wednesday, September 23, 2009 - link

    I highly recommend the Uniden DECT6.0 models. The kit I got about 6 months ago to replace crappy old units was ~$110 for 3 units. Additional units (if your manion requires :) can be added easily to the setup for another $30-40. No wireless issues whatsoever. And it's the first phone I've been able to use out to my curb without issues (brick exterior with plaster walls = bad signal). The only gripe I have is there doesn't appear to be a way to change the caller ID name when it comes in. You can program your own numbers in, but when you receive a call it always shows only how caller ID recognizes it.

    Got mine from the egg.
    Reply
  • mschira - Monday, September 21, 2009 - link

    on my Atom based laptop. Flash is mostly used for annoying advertising. And it eats CPU, makes the budy slow.
    Booo to flash...
    M.
    Reply
  • dnd728 - Tuesday, September 22, 2009 - link

    If Adobe merely added a button to freeze all Flash animations or even just freeze all Flash in non-active tabs, then like a hundred power plants could have been scraped… Reply
  • JarredWalton - Tuesday, September 22, 2009 - link

    Which is what FlashBlock does. :) Of course, Linux browsers by default don't normally auto-play Flash I don't think. I enabled that with Firefox and then used FlashBlock to stop it, just for an "apples-to-unoptimized-apples" comparison to Vista. Reply
  • bigboxes - Monday, September 21, 2009 - link

    Whatever. I use adblock plus and see few ads. Flash, however, is a part of how we view the internet. It's a part of our experience. If you want a text only internet please feel free to step back in the wayback machine to 1988. Reply

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