14 DAY TRIAL // Respected security researcher Robert Hansen has published a study of how web technologies impact the energy consumption on the web client side. The study outed Flash rotating ads as being the most power-hungry website elements.
Robert Hansen is the founder and CEO of the SecTheory security company, and a known figure in the security circles. His expertise is focused on web security aspects, and he was recently in the spotlight along Jeremiah Grossman of WhiteHat Security for discovering several critical user interface redressing (a.k.a. Clickjacking) vulnerabilities affecting all major browsers.
Mr. Hansen explains in his paper, entitled Browser Power Consumption, the reasons behind measuring the power drain when browsing different popular websites. “In the modern era of green energy and power conservation, it is worth looking at methods of conservation that are closer to the average consumer.” He warns that, because of several shortcomings in the methodology used, this study cannot be considered a scientific one, yet it produced interesting and noteworthy results. “While this exercise was not a real scientific study, it provided enough evidence to point to clear areas of power consumption in every day web applications.”
The researcher used simple tools like the Windows Task Manager and the Kill A Watt application to measure the amperage during the tests. “By multiplying amperage by voltage, it becomes rather easy to estimate the average draw,” he explains. For comparison reasons, he performed the tests on the latest stable versions of both Internet Explorer and Firefox browsers, and used the most popular websites in the Alexa 100 list for the United States.
The technical details of the test setup as well as the drawbacks and caveats are noted in the research paper, and, regardless of the many variables involved, like the dynamic nature of pages, which changed content from test run to test run, the average results remain relevant. According to them, all the dynamic web technologies such as Flash, Silverlight, JavaScript, Java, VBScript and AJAX increase the power consumption. This is because, when processing such applications, the browser will require more CPU power and, consequently, more energy is drained.
With Flash being deemed the least “green,” it is still questionable if that is because of the technology itself or the way in which it is used on websites. For example, the very common Flash-based rotating ads are amongst the page elements responsible for draining a lot of power, specifically because of their rotating nature. “They could have easily been programmed to stop rotating after a few seconds, to return the site to a conservative power usage, but they weren't,” notes Hansen.
AJAX is next on the power-hungry list of web technologies after Flash, but “JavaScript, Java, VBScript and Silverlight all easily could have caused problems, and they should not be discounted as possible culprits for power consumption,” says Hansen. Another interesting part of this research is the test performed with Firefox with the NoScript and Adblock Plus extensions enabled. These extensions are specifically designed to block such dynamic technologies on pages while surfing. Browsing with this setup revealed a decrease of 0.1 Amps and over 11 Watts in power consumption. This is impressive, because, as Mr. Hansen points out, they represent “the same savings as it costs to run a 40 Watt compact fluourescent light.“
Adobe's John Dowdell comments Hansen's research on his own blog. “It's certainly possible that ads delivered as SWF could be piggy. Adobe hasn't installed framerate chokes for the content you make, and advertising publishers have general guidelines for not being piggy. But considering that many popular webpages never stop loading due to the multitude of third-party content requests, it's definitely possible that some of the advertising on those pages could be increasing your CPU's general load to measurable degree,” he explains.
Robert Hansen concludes that “it does appear that it would be possible to surf in a 'green' manner.” He points to the fact that “while the differences may appear to be minor in power usage, power consumption does add up over time.” While this research may fall short of being scientific, which it doesn't even claim to be, it is still at least interesting, and, as the security expert himself thinks, it could serve as a starting point for more pertinent and exact testing of these aspects.