Admittedly, its not difficult to imagine a scenario where less CPU cycles result in less power drain and this method isn’t going to magically extend your battery life by much but its nice to see the theory tested to the extreme.
SecTheory.com took a notebook PC, a couple of browsers and measured the battery drain on the Top 100 Alexa sites. They then took the worst offenders, that is, the ones that took the most power drain, and blocked script and ads using NoScript and AdBlock Plus. The results were quite significant. On a Dell Inspiron B130 notebook, with a 1.5GHz Celeron M processor and 1 Gig of ram, running fully patched Windows XP SP2, the power consumption when browsing the worst offending sites dropped by 11W, a 20% reduction. If its a 25W TDP CPU we’re talking about here, I can believe the results because browsing website has grown to be a very CPU intensive task.
The effect would be much less on netbooks and UMPCs but I would expect the same test to save 1W average which is about 10% – about 15 minutes for a device with a standard battery. Of course, its not really normal to be picking the worst offending sites and continuously hitting them either. Under normal browsing use, you probably wouldn’t notice any difference but there’s something else you need to be aware of.
Script not only takes CPU and battery life, it takes time. Time to execute, render and in some cases, time to fetch the remote code. By disabling script you significantly improve browsing speeds on low power devices and by definition, you save battery life. I tried it a few weeks ago with the noscript plugin and I’ve seen many comments on UMPCPortal from users that also use the technique. It really works! You lock yourself out of application sites like Google reader initially but it doesn’t take any effort to enable exceptions for these sites as you go along. No more hung page loads waiting for remote sites to time out. No more of those terribly annoying auto-start video ads that make browsing on a low-end PC a misery. There’s even an improvement in security. Its a win-win-win!
Try it. Install the noscript plugin and see how you get on. Yes, I risk killing all of my advertising income if everyone does this on all their devices and I’m sure there are bloggers out there that will read this and cringe but I trust you’ll only use it on your netbooks and umpcs and put the exception in for your favorite sites! Long live the choice between simple html and web2.0!