Gateway NV52 (AMD) - Battery Life
We'll start with AMD's mobile platform, which we have already dissected in previous reviews. Here's the quick rundown of specifications, and as much as possible we updated all applications, drivers, and OS components to the latest versions. The ATI drivers for Windows XP and Windows Vista are slightly older than the Windows 7 drivers, but unfortunately we are not able to install "reference drivers" on ATI-based laptops for Vista or XP. Thanks OEMs!
| Gateway NV5214u Test System | |
| Processor | AMD Athlon 64 X2 QL-64 (Dual-core, 2.1GHz, 2x512KB L2, 65nm, 35W, 667MHz FSB) |
| Memory | 2x2048MB Hyundai PC2-5300 @ DDR2-667 5-5-5-15 (Hyundai Electronics HMP125SEFR8C-Y5) |
| Graphics | Integrated ATI Radeon HD 3200 Driver version Cat 8.582-090203a (Feb 03, 2009) 40 (8 x 5) Shaders at 500 MHz |
| Display | 15.6" Glossy WXGA (1366x768) AU Optronics B156XW02 |
| Hard Drive | Seagate Momentus 5400.6 320GB 5400RPM 8MB (ST932032 0AS) |
| Optical Drive | 8x DVDRW (LG Electronics GT20N) |
| Battery | 6-Cell 10.8V, 4400mAhr, 47.5Whr |
| Operating System | Windows Vista Home Premium 64-bit |
| Price | NV5214u available at Best Buy for $500 |
We are comparing performance and battery life on a single system, so system specifications don't necessarily matter. This is an apples-to-apples comparison between several different operating systems using the same hardware. Here are the results.
So we have some good news and some bad news. The good news is that Windows 7 definitely shows some battery life improvements relative to Windows Vista. The bad news? We're still awaiting the official launch of Windows 7… and then we need to start from scratch with battery life testing on future laptops, since as we don't want to compare apples and oranges.
Using the Balanced profile, Windows 7 ends up providing 11% more battery life than Windows Vista. When we switch to the Power Saver profile, the margin of victory shrinks to 5%. The wildcard in these tests is Windows XP, which delivered the best battery life using its Portable/Laptop profile (by 2% over Win7, so it's almost a tie). However, it also achieved the worst battery life using the Max Battery profile (Win7 wins by 6%).
The margin of error between runs is around 3%, but we try to run each test multiple times and take the best result… unfortunately, when you have one laptop and about 30 battery tests to run on it, each requiring around four hours (with recharge time), repeating each test is a bit too much to ask for. Case in point, the Gateway NV52 originally had a score of 175 minutes on one run with the Power Saver profile, which seemed too high; rerunning the test three times showed that there must have been some other factor involved (i.e. perhaps a Flash ad server was temporarily down). Feel free to take the figures with a grain of salt, and we have some additional data later to verify the standings.
Clearly, power profiles are making a big difference depending on the operating system. Windows XP saw the least benefit, improving just 4.5% by using the power saving profile. Windows 7 comes in second, with an improvement of 13%. Then we have Windows Vista, which delivers an astounding 20% improvement in battery life just by switching the power profile.
Ubuntu is a little bit more difficult to assess, but clearly Ubuntu doesn't come anywhere near matching Windows. Using the power saver profile and Firefox, Windows Vista beats Ubuntu by 38%. Even if we factor in the power profile (Ubuntu doesn't appear to have a way to manage power profiles like Windows), that would still be a difference of around 15% in favor of Vista. Flash is extremely sluggish on Linux, however, and the margin of victory decreases when we use the FlashBlock add-on. At that point, Windows Vista only wins by 19%, which we could attribute to the power profile. That's still a significant difference in battery life, and we're using the worst of the Windows OS options for comparison. We didn't have time to test with other operating systems using Firefox or FlashBlock, largely due to the amount of time we spent trying to get Ubuntu to work properly in the DVD playback results.
The DVD playback results are completely different from the Internet battery life results, with the power profile having virtually no effect on battery life. The three Windows versions had the same score, within one minute, using each profile, so using the Power Saver profile is clearly no panacea. On the other hand, there are definite differences between the three Windows OSes. Ubuntu crashed repeatedly during DVD playback, sometimes to the point where we needed a hard reboot. Changing to the open-source MESA drivers fixed the situation with DVD playback, but under that test scenario Ubuntu manages a rather unimpressive result. It looks like ATI's drivers would last just over two hours with Ubuntu in DVD playback, so they definitely do better in terms of power optimizations. Looking at the Internet battery life with the open-source MESA drivers, there's clearly a lack of power optimizations (despite enabling dynamic clocks in the xorg.conf file).
Overall, Windows 7 appears to improve battery life for DVD playback by over 20% relative to Windows Vista, but the improvement is only about 6% relative to Windows XP. The story for Internet surfing is far more confusing. If you use the Balanced power profile, Windows XP beats Windows Vista by 13% and just edges out Windows 7 by 2%, making it the best option. Turn to the Power Saver profile and Windows 7 is the leader, 6% ahead of XP and 5% ahead of Windows Vista. Ubuntu isn't even in the running, with Vista offering up to 37% more battery life using Firefox; blocking Flash elements does help Ubuntu, but it also helps Windows and the gap shrinks to only 19%. Makes you wonder if Flash content is actually worth having, doesn't it?
Facebook
Twitter
RSS
106 Comments
View All Comments
JarredWalton - Tuesday, September 22, 2009 - link
I don't think it works quite like that. If you set it to 0%, I believe that's the minimum CPU speed (i.e. 5.25 x 200MHz on the NV52 and 6 x 200MHz on the NV58), while the higher percentage may try to target a maximum speed. 100% would be the normal CPU speed, but would 50% be half-way between minimum and maximum?I'd have to investigate more, but I do remember testing with CPU-Z and seeing CPU clocks go well above the 50% mark. I think at best it's approximate, as you suggest, and how accurate it is likely varies greatly with the CPU - and even BIOS options.
trochevs - Tuesday, September 22, 2009 - link
Looking the starting times (startup and resume) I have the feeling that Ubuntu has some kind of problem on your hardware. I have quite bit experience with Dell and Lenovo and Ubuntu 9.04 is always faster to boot compare to any Windows. It is not only my experience, but I am doing test on one senior citizen and one teenager. They both agree with my observation. You should press Alt-F1 during the boot and check for any errors. Gateways could have some additional peace of hardware that does not work correctly under Ubuntu and the kernel has to wait to time-out.In regards out of the box experience you should get hold of the system that is optimized for Linux (Ubuntu) just like the Gateway is optimized for Windows. www.system76.com or Dell http://www.dell.com/content/topics/segtopic.aspx/u...">http://www.dell.com/content/topics/segt...s=19&... would be good start. Then you don't have to fool with drivers. I would love to see how much optimization has been done by System76 and Dell.
ekul - Tuesday, September 22, 2009 - link
It's true; ubuntu 9.04 boots very quickly and 9.10 will be even better. On my netbook and my desktop 9.04 boots in a lot less then 30 seconds. I agree something isn't quite right with the boot procedure.The other thing to keep in mind for linux boot times is once the desktop is displayed the system is fully up. No background loading, no delayed startups. On Vista and 7 I find after the desktop appears it will take another 30-45 seconds before the HD is done reading and the system is responsive
oyabun - Tuesday, September 22, 2009 - link
Thank you very much for an enlightening article. I am one of the people who indeed care for battery life!Regarding your testing methodology where you drain each battery over and over again, wouldn't it be more efficient to take the battery out of the equation (and physically remove it) completely? Just measure the Wh consumed by the power brick during 30 or 60 minute runs and extrapolate to the capacity of the battery. That would greatly reduce your testing times.
You should of course measure at the DC end of the transformer, otherwise you should factor in it's efficiency.
You could even calibrate the whole procedure with a single battery powered run. It certainly beats what you are currently subjecting yourself to! :-)
Keep up the good work!
JarredWalton - Tuesday, September 22, 2009 - link
My experience is that laptops typically switch to different power states on AC vs. DC power, even if you have all the settings the same. It's possible to estimate battery life, but I do like to do "real world" testing where possible. Anyway, it's not a bad idea and I may do a follow up article at some point looking at just the power numbers. Taking the power transformer efficiency out of the equation isn't something I'm equipped to do right now, unfortunately. I can measure power at the outlet... and that's it. And it's only accurate to ~1W there so I'd need a better device than my current Kill-A-Watt.BTW, have you ever stared at a small Kill-A-Watt display while running tests? Frankly, running battery tests where I can walk away and collect the results later is less painful all around! :)
oyabun - Wednesday, September 23, 2009 - link
Of course a Kill-A-Watt won't cut it! You need a datalogger on a separate PC and a power gauge, logging the total energy consumption over any period of time unattended. With such a setup you would be able to measure from the DC side by splicing the wires leading from the transformer to the notebook. And, naturally, a datalogger support more than one gauge, so you could measure in parallel.I understand what you mean when you say that power profiles behave differently under AC. It is possible though your (and mine) experience is based on Windows XP. Perhaps Windows 7 are more consistent.
oyabun - Wednesday, September 23, 2009 - link
I didn't see the comments by Kibbles before. Our posts convey the smae message!And I concur, the power supply testing team appears to have the tools for the job.
strikeback03 - Wednesday, September 23, 2009 - link
Yeah, IIRC they're also in Europe, while Jarred is in Seattle or somewhere out west.JarredWalton - Wednesday, September 23, 2009 - link
There's more to it than that, but suffice it to say I don't have power testing equipment and it's not high on my list of priorities right now. Rough estimates are sufficient on the power side of the equation, since you get whatever power brick the laptop comes with. It's not like you can upgrade to a more efficient power brick with a Dell laptop.Kibbles - Tuesday, September 22, 2009 - link
"maybe borrow it from the powersupply setting team"I meant "powersupply testing team".
Also for the convenience of being able to walk away. As long as you get a voltmeter with logging capability, you can leave it to do it's thing and just pull up the logs.