Use Firefox? Download Firefox 7, it Reduces Memory Use & Increases Speed
Firefox 7 is now available to download for all supported platforms, the new release has an emphasis on improved memory management and speed, and it does provide a noticeable difference in snappiness when loading pages or browsing the web.
The benefits are best seen if you keep Firefox open for a long time (who ever closes their web browser anyway?), use a lot of tabs, and view pages with a lot of images or text, and in my usage I can confirm it feels more responsive and has a lower memory footprint in OS X. The Mozilla dev team suggests that version 7 will use as much as 50% less memory, but I haven’t seen that dramatic of a difference. If you use Firefox for any browsing purposes or rely on it for plugins like Firebug, it’s well worth downloading.
As usual, Mac OS X, Windows, and Linux are available concurrently. If you have plugins installed, expect a few to nag about compatibility, but they all worked for me anyway.