The Test

Overall, many factors go into web browser battery usage, like GPU accelerated rendering and content caching. Chrome, despite its aggressive timer usage, may still be more battery efficient than other browsers. I should note that AnandTech has historically used Safari on OS X and desktop IE on Windows devices when performing battery life testing.

With this article we are debuting a new browser benchmark tool. Developed in house, this tool automates the usage of a desired web browser as if a user was sitting at the computer. It performs common tasks like launching and closing the browser, opening and closing tabs, loading websites, and scrolling through longer articles. As usual, the websites visited are popular sites cached on the AnandTech server, so the content of the sites does not change between runs. Additionally, the browsers are all run in private browsing mode to prevent local content caching from interfering with reloading our limited set of server-cached sites.

Browsers tested:

  • IE11 Desktop Mode v11.0.9600.17207 (Update versions: 11.0.10 KB2962872)
  • IE11 Modern (Metro) Mode
  • Firefox 31.0
  • Safari 5.1.7
  • Chrome 36.0.1985.125 m
  • Chrome 37.0.2062.68 beta-m (64-bit)

There are several other browsers we would have liked to test, however, due to the time intensive nature of battery life testing, we chose to focus on the most popular browsers. We also chose to test the beta version of Chrome as it is a significant update. Chrome 37 changes from 32-bit to 64-bit and from GDI (legacy) rendering to DirectWrite (modern) rendering. This makes the browser actually usable and no longer blurry on HiDPI displays.

To take advantage of operating system and hardware advances since our last test, testing was performed on the high end model of the Dell XPS 15 (9530) late 2013 edition running Windows 8.1 with all updates as of this writing.

Dell XPS 15 (9530) Late 2013 Specifications
Processor Intel Core i7-4702MQ
(Quad-core 2.2-3.2GHz, 6MB L3, 22nm, 37W)
Chipset HM87
Memory 2x8GB DDR3-1600
Graphics GeForce GT 750M 2GB GDDR5
(384 cores, 967MHz + Boost 2.0, 5GHz GDDR5)

Intel HD Graphics 4600
(20 EUs at 400-1150MHz)
Display 15.6" Glossy PPS 16:9 QHD+ (3200x1800)
(Sharp LQ156Z1 Touchscreen)
Storage 512GB mSATA SSD (Samsung SM841)
Optical Drive N/A
Networking 802.11ac WiFi (Intel Dual-Band AC-7260)
(2x2:2 867Mbps capable)
Bluetooth 4.0 (Intel)
Audio Realtek HD
Stereo Speakers
Headset jack
Battery/Power 9-cell, 11.1V, 8000mAh, 91Wh
130W Max AC Adapter
Front Side N/A
Left Side Battery Charge Indicator LEDs
Headset jack
2 x USB 3.0
1 x Mini-DisplayPort
1 x HDMI
AC Power Connection
Right Side Flash Reader (MMC/SD)
1 x USB 3.0
1 x USB 3.0 (Sleep Charging)
Kensington Lock
Back Side Exhaust vent (inside LCD hinge)
Operating System Windows 8.1 64-bit
Dimensions 14.6" x 10.0" x 0.3-0.7" (WxDxH)
(372mm x 254mm x 8-18mm)
Weight 4.44 lbs (2.01kg)
Extras 720p HD Webcam
87-Key Backlit Keyboard

The latest edition of this laptop upgrades to the "Haswell Refresh" i7-4712HQ with an extra 100 MHz clock rate compared to our test laptop. That should have little to no impact on the browser battery life testing.

Windows Timers Results and Analysis
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  • zodiacsoulmate - Tuesday, August 12, 2014 - link

    Also where is the CPU load graph? would love to see it ! Reply
  • NatePo717 - Tuesday, August 12, 2014 - link

    Could we see some numbers for Pale Moon? Reply
  • BillBear - Tuesday, August 12, 2014 - link

    Safari is already scriptable using OSX's built in Applescript scripting system, so you don't have to invent anything new. At worst you'll have to pick up a bit of a new scripting language.

    I'm looking forward to seeing how Apple's claim that they spank the other browsers on energy efficiency pan out..
    Reply
  • Oxford Guy - Wednesday, August 13, 2014 - link

    There is also a program called Automator. http://macosxautomation.com/ Reply
  • mabellon - Tuesday, August 12, 2014 - link

    Could you clarify the following please: "Additionally, the browsers are all run in private browsing mode to prevent local content caching from interfering with reloading our limited set of server-cached sites."

    Don't most browser have one big session for all in-private tabs? So there will be caching across tabs and sites until you close every instance?

    Please consider using a more standard laptop in the future. A quad core 37W CPU seems incredibly unrealistic. Something more along the lines of a 15W/17W CPU would make sense. The power profile of an ultrabook will likely be vastly different to this beast. That would seem to matter a lot more given the trade off in rushing to idle, and the cost of idle wakeups will vary by CPU by some amount. Just my 2c.
    Reply
  • Stephen Barrett - Tuesday, August 12, 2014 - link

    Good question. The automated test does open up several private browsing tabs but it closes them all (and the entire browser) between iterations.

    Intel power gates unused cores so there shouldn't be too much difference between a dual core and a quad core for idle power. I agree it would be interesting to test other hardware as well. Unfortunately these tests already take days, so using an even lower power laptop will make it take a really really long time and would probably just exacerbate the differences we already observed even more.
    Reply
  • KhalidShaikh - Tuesday, August 12, 2014 - link

    Great write up. Reply
  • lucas1024 - Tuesday, August 12, 2014 - link

    Bad news - I checked the timers with Firefox on two different machines and on both Firefox is maintaining a 1ms timer. Reply
  • linj - Wednesday, August 13, 2014 - link

    I can confirm this. Tested Firefox with a new profile (no extensions), and navigating to most websites (but especially Flash-enabled ones) will ramp up the 1ms timer. Closing down to even a blank page doesn't release it. Reply
  • Stephen Barrett - Wednesday, August 13, 2014 - link

    Strange. I did not see that in my testing. I wonder what the difference was. Reply

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