The latest development builds of Google Chrome include a way to make the browser clean up its act and stop hogging RAM. It’s easy to enable, and even easier to use. Just keep in mind that you must be running a dev channel build.
Open up the shortcut for Chrome (if Pinned on Windows 7, Shift+Right-Click for the context menu), and then add the following—note that there should be two dashes there.
Now you can right-click on the title bar, or use the Shift+Esc shortcut key to bring up Chrome’s Task Manager.
Hit the Purge Memory button, and it should clean up some of the memory (though not all of it).