AnandTech loaded three sites into the tabs on their test web browsers, waited 60 seconds, and then reloaded all three tabs. To run the tests they used AMD and Intel laptops (Gateway NV52 and NV58) and a netbook, the ASUS Eee PC 1005HA.
The tests using the AMD Gateway NV52 show a dramatic difference between the best performing browser, IE8, and the worst, Safari 4. IE8 provided 33% more battery life under Windows Vista than Safari 4.
Safari performance using the Intel Gateway NV58 closed the gap a bit more; however, it still trailed the best option, IE8, by 23%.
Unlike the other laptops, almost all of the browsers offer the same battery life on the ASUS netbook, the major exception is the Safari 4 web browser which comes in last, again by a large margin. Chrome performed best at 36% more battery life on the netbook than Safari. IE8 came in second.
You may want to consider these results if you need to squeeze that extra time out of your battery life. Hopefully we will see a Mac OS X comparison soon...