I don't know what its like under other OSs, but on my Win7 AOA the new Firefox 4 is simply incredible. I've used Firefox religously for years. But running Firefox 3 under Win7 on the Aspire One would sometimes cause pagefile.sys to kick in on my system (often a few mins after launching the browser), thrashing my drive and making everything slow as molasses for a minute. No such problem with Firefox 4. It's extremely fast and is not causing any system slow-downs at all. Just had to share, as I am well impressed: [URL]http://www.mozilla.com/en-US/firefox/features/[/URL]