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.
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ascl - Tuesday, September 22, 2009 - link
I was reading this thinking that it was an unusually bad review from anand.... then I reached the conclusion 2 + 3 and my complaint was answered! Using randomised web testing is terrible if you want repeatable results. Use an internal server with a fixed set of pages (and ads).Kudos!
vailr - Tuesday, September 22, 2009 - link
Maybe compare battery life on a MacBook Pro running OSX Snow leopard vs. Windows 7 64-bit/Win XP 32-bit (in Boot Camp) vs. Ubuntu(?). Using VLC Media Player sequenced to play a series of several DIVX movies, for finding the running time under each OS.gstrickler - Saturday, September 26, 2009 - link
Anand has already done that with a MBP and OS X vs XP (and maybe Vista). Anyway, it would be good to see it repeated with Win7 in a couple months when they've had time to produce some reasonably power efficient Win7 drivers.In any case, a MBP is a great platform for the task, it will run all those OSs, the Nvidia chipset is well supported in all of them and it's pretty power efficient. Of course, with it's battery life, the tests might take a while.
Gamingphreek - Tuesday, September 22, 2009 - link
Battery life in Linux, as it is a *nix based OS, needs configuring. You claimed that you couldn't find it, but honestly you need to find someone who has *nix experience then because it is honestly the most customizable of the OS's.Additionally, while you did a good job in following that website for advice, staying with the 'Safe' configuration is a grave error. All that merely does is use an old version of MESA (OpenGL driver) and an old Intel driver. I would honestly like to see you try out the 2.6.30.5 or the 2.6.31rc kernel along with the most up to date drivers from the XorgEdgers repository. Performance with those optimizations is honestly quite remarkable.
Furthermore, I would suggest looking over lesswatts.org as well as running the PowerTOP application to see what is unnecessary. For instance, I have a script that disables my PCMCIA slot given that I do not use it. I also have my RJ11 based modem disabled. I have LaptopMode enable automatically when I unplug A/C power and disable when I plug in A/C power.
Additionally, why did you turn off auto dimming?? That is a great feature that severely crippled the performance of Ubuntu yet again.
As for Firefox/Shiretoko (Shiretoko is the codename for Firefox 3.5) that is a known issue with lazy programming. Downloading the Noscript or Adblock extension helps immensely with performance. Additionally Shiretoko/FF3.5 has a vastly improved engine when compared to FF3.0.
Additionally, I don't believe you stated what file system you were using. EXT4 is vastly superior to EXT3 (While it isn't the default, among Linux users, it is rare for someone to choose EXT3 over EXT4) - especially when boot times are involved. Even still, it sounds like there was a broken script or something - Ubuntu 9.04 has the fastest startup/shutdown I have ever experienced.
Honestly, Ubuntu seemed to draw the short end of the stick here. It takes time to configure the OS - I honestly expect more time to be given to configuring it like the other ones.
smitty3268 - Tuesday, September 22, 2009 - link
While I agree with most of your points (you can definitely tweak linux down to the bare bones much more than something like XP to save power), I think it is perfectly acceptable to use a default distro that is commonly used. After all, he didn't go through the Windows registry, disabling services and hacking stuff there either.But in the end, let's face it. Firefox and Flash are horribly optimized for Linux. It's not exactly a surprise that they suck down more juice, given that they usually take about 5 times more CPU power than under windows.
Gamingphreek - Tuesday, September 22, 2009 - link
Well that is the inherent difference between Linux and Windows.Thats like saying you aren't going to download and install drivers for Windows - Linux comes with all of them...
And as a slight correction, Firefox isn't really the problem and Flash is horrible for any/everything BUT Windows.
JarredWalton - Tuesday, September 22, 2009 - link
As stated, it wasn't intended to be a Linux review. This is a well-known Linux distro that is supposed to be "easy". I don't have the time nor inclination -- just like 99.9% of users -- to go into detailed steps for hacking and modding Linux. I fully understand that it is highly customizable, but so is a car if you're inclined to go that route. I drive a stock vehicle, and I use a stock OS.Downloading drivers isn't the same thing as downloading the latest kernels, creating your own conf files, and manually entering all sorts of settings that help enable/disable items to provide better power saving. My conclusion pretty much sums up my feelings: the out-of-box experience for Ubuntu is nothing special for a laptop, and if you are expecting it to "just work" you'll be disappointed.
Given how much is available for tweaking in the Linux community, I'm frankly surprised that no one has apparently spent the time to make the default configuration far more sensible and easier to live with. I know how much fun it is to download and compile programs and edit configuration files, but I'd rather just have an easy interface that works without a ton of effort.
I also fully recognize the inherent problems with Flash, so I put in numbers with Firefox and FlashBlock. It helps, but it doesn't help enough to equal the default Windows setup. There are other browser options of course, and if/when I get time I'll see about looking at some of them.
ekul - Tuesday, September 22, 2009 - link
Ubuntu is a poor distro for battery life out of the box as many of its default settings belong on a desktop or even server system. With a bit of tweaking though it can easily get better battery life then windows. My netbook struggled to get 2 hours in XP, in ubuntu I can easily see 2:45 or more.As has been mentioned by at least one other commenter use the powertop tool (sudo apt-get install powertop && sudo powertop). This was written by intel to help find applications and drivers that were waking up the cpu too much and hurting battery life even if they didn't appear to be using very many system resources. The tool itself looks for many settings that are not optimal for battery life and offers to correct them for you so you don't have to go on a treasure hunt at all. I'd love to see what kind of improvement could be made with that tool alone.
As an aside, a major oversight is idle battery life. All of your tests feature the OS as the minor player in the war against power consumption. In each test you have an application eating the majority of the resources. You should fully charge the battery and let the laptop idle at the desktop until it dies, testing each OS's ability to sleep long running processes and services. Perhaps leave an office suite, browser idling on a page and wifi connected to stop the runtime for taking too long.
Finally using flash heavy websites heavily skews the results for both OS and browser battery life tests since you are sending both into battle missing limbs. It is well known flash is poorly written software at the best of times, causing well over 60% of all firefox and IE crashes. It has rudimentary 64 bit support, doesn't support hardware acceleration on anything but windows and if it isn't playing video (covered by the dvd test) is almost certainly on the page to serve an ad. No browser has any sort of control over flash (though chrome does its best to reign it in) so your browser tests amount to little more then a test of flash. Flash sucks even in windows but in linux it is truly awful (as is almost all closed source code for linux).
JarredWalton - Tuesday, September 22, 2009 - link
The second batch of sites was hardly Flash-heavy. Yahoo and MSN have one Flash ad, YouTube has none, and the Facebook login page is just text and images.FWIW, I did run an "idle at desktop" test on Ubuntu on the NV52 and got a time of 204 minutes. That compares to 242 minutes under Vista, or a 18.6%. There are a LOT of other things I still need to look at, however -- including different power schemes, tweaked profiles, etc.
If I'm going to try to improve the Linux results in every way possible, it's only fair to do the same for Windows.
ekul - Tuesday, September 22, 2009 - link
Because the linux and windows philosophy is so different a different approach has to be taken to setting them up and running them. With windows initial setup is very simple and has vendor support for things like drivers. Over time problems begin to appear and cleanup/formatting becomes necessary. Most linux distros integrate all possible hardware support and target lowest common denominator hardware to ensure broad compatibility at the expensive of performance. Once they have been tweaked they will continue to run indefinitely at that level.With windows you have ease now for pain later. With linux you have pain now for ease later. This means running things like powertop and changing the init options to run in parallel would be the same as cleaning a registry in windows rather than something like disabling services in windows. I spent one afternoon tweaking my netbook and now it runs much smoother and faster then it ever did with windows plus the battery life is longer. Changing config options and customizing for your hardware is the reality with linux the same way random problems cropping over time is the reality with windows. If linux distros are to be punished for ease of setup issues then windows must be punished for altered performance 6 months from now. Linux is getting better however, and different distros ship with very different defaults. Ubuntu is really debian unstable repackaged for the server/desktop which means at its very heart it is a server distro. For future tests opensuse may be the best choice to represent laptop/desktop defaults.
FWIW if you want to find the real options in linux for power management you should look in /sys/devices/system/cpu/cpu0/cpufreq/. The options in the gnome power management panel only really deal with monitors. But again 3 minutes with powertop and I'm certain you will see an improvement.