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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  • Kibbles - Tuesday, September 22, 2009 - link

    If all you have is a killawhat meter then that'll be pretty inaccurate. Not just because of the 1W accuracy but also measuing at the outlet you are also including the inefficiency of the powersupply.
    However I do agree that using the battery is throwing an extra variable into your equation. How big is it? I don't know. But I do know they don't always charge to the same capacity, and their capacity changes overtime.
    I don't know if it's possible, but I would think the best option would be to have a DC source modded into the battery connection. Then measure the #W-h used. You would probably need a good variable DC supply and voltmeter to do this (maybe borrow it from the powersupply setting team?). Even then I don't know if you can do that, I think my laptop has like 6 pins on the battery. There's probably some connection for charging, some for battery status, and then the discharge connections.
    The second option I see is putting a voltmeter on the DC-out side of the powersupply going into the laptop. You could run the benchmark without the battery for an equivalent duration and see if the W-h is close.
    Reply
  • n0nsense - Tuesday, September 22, 2009 - link

    Power savings in Ubuntu are far from optimal.
    I was more than surprised to see that even very basic features may or may not work.
    For example on my Gentoo box each core frequency scaled separately.
    On Ubuntu some processors are not supported. After all I thought that engineers at Canonical have better kernel understanding than me.
    As for the tests, dim option is helping with battery life.
    I don't remember such difference in battery life from my experience. Both Linux and windows where capable of ~3Hr on my laptop.
    From my very personal point of view, Ubuntu is sluggish. I compared Ubuntu, XP, 7, Debian and Gentoo performance on IBM X31 with 1GB ram.
    It started without Gentoo (It takes a while to setup fully optimized Gentoo box). Ubuntu and 7 where (IMHO only)the slowest. Debian and XP where just fine. But since I wanted more, i did the Gentoo thing. It was more than worth it.
    With Ubuntu it was overall sluggish feeling (some tests will show much better performance under it than in windows). But feeling is important when you use something. Even more important than some numbers.
    7 ... Same sluggish Vista with facelift and few tweaks that can be manually done.
    Watching icons drawn few seconds after menu displayed was more than enough. It is more stable, can work longer without reboots, but nowhere faster than XP.
    Debian with Gnome was nice so was XP. Anyway I'd stay with Linux since it's more customizable and have few useful things that make me feel handicapped in Windows.
    Gentoo once again convinced me that it worth each second (it took more than 2 days on X31. should be much faster on any dual/quad core CPU and/or using distcc). But, not everyone can do it. Even "experienced" Ubuntu/Fedora/Suse (or whatever mainstream distro) may find that his understanding of "how staff works" is not on the required level.
    Anyway it's quiet a change to see Linux participating in review.
    Good job guys :)
    Reply
  • lordmetroid - Tuesday, September 22, 2009 - link

    I'll be running Arch Linux on my nettop, I tried gentoo 4 years ago from stage 1 and that was a nightmare to get installed. Maybe I should try it again but Arch Linux seems to be more interesting at this point as it had many of the packages I want in its repositories that I couldn't find in gentoo. Reply
  • stmok - Tuesday, September 22, 2009 - link

    Running Arch Linux here on my ThinkPad T43...Much better than Ubuntu.

    Ubuntu feels bloated. Heck, even Xubuntu feels bloated.
    Reply
  • void2 - Tuesday, September 22, 2009 - link

    30..40 seconds to boot WinXP on modern CPU? That's sad. I get 7..8 seconds (boot menu to desktop, add your machine POST time yourself) on a comparable CPU (Athlon 64 X2 3800+). Clean OS, no SSD, no messing around with disabling services etc. How? Use Boot Cooler (www.bootcooler.com). It is free. Reply
  • lyeoh - Tuesday, September 22, 2009 - link

    Why should anyone use bootcooler? The website doesn't even say what the program is _supposed_ to do, and how it achieves it. I don't see much on the web that describes or tests what it _actually_ does (as opposed to just claims), the limitations etc.

    It could be a trojan for all we know.
    Reply
  • void2 - Tuesday, September 22, 2009 - link

    If you haven't noticed, the website is under construction. Detailed explanation of how Boot Cooler works is included in readme.txt (in short - disk reads prefetching). And of course there are no reviews yet - the project is still in beta. Reply
  • orionmgomg - Tuesday, September 22, 2009 - link

    I love antech - waiting for the radeon hd 5870 info to hit - looking at this artical - something about your battery lasting longer on your lap top...


    WHO CARES!!!

    Give me a brake - you spend so much time on analizing minutes of extra juice it a fly is in the room or not! WHO CARES?

    Plug your lap top in the wall - dont expect it to last any longer than it does when you have a full charge and it runs out of juice.

    Once you know how long it lasts - realize your screwed - or should I say attached to the power cord!

    Oh - did I mention - who cares?

    Thanks for all your other articals!

    Reply
  • orionmgomg - Tuesday, September 22, 2009 - link

    I love Anandtech*^ Reply
  • JarredWalton - Tuesday, September 22, 2009 - link

    If you haven't figured it out, I'm the mobile reviewer at AnandTech, and my articles are about mobility. Writing articles about laptops doesn't mean I'm delaying any CPU or GPU reviews -- unless they happen to be mobile CPUs/GPUs. If you don't care about laptops, you don't need to read most of my articles, but please don't make the mistake of assuming no one cares. When people use a laptop on the road and don't have a chance to plug in, articles like this are very useful. If you never use a laptop, great; some people do and that's my target audience. Reply

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