The big advance in Chromium (and Chrome) is that each tab in the browser is a separate process in OS X. As a user, what this means to you is that if you load a page that crashes due to bad JavaScript or some other reason, you won't lose your entire browser.

Instead, the tab (or window) that loads the crashing page will have to be shut, and you'll see the crash message (or whatever it evolves into) as seen at right in that tab or window--but all of your other windows and tabs will remain intact. This is a tremendous advance in terms of usability; I can't count the number of times I've lost a nicely-set-up collection of tabs in Safari or Firefox just due to an issue on one tab.

However, this new feature isn't without its costs--in this case, the cost is RAM usage. Each new blank tab I opened in the browser took about 20MB of real RAM. As those tabs then gained content, their RAM usage would increase.

All told, that's about 336MB of RAM for my seven-tab browser. This isn't all that different than Firefox or Safari, but as the number of open tabs and windows increases, the numbers start to diverge. Opening a new tab or window in Firefox or Safari only adds about 2MB of real RAM usage to each program's memory footprint. A quick test with 15 open tabs (loading the same sites in each browser) showed Chromium requiring over 520MB of RAM versus 310MB for Safari.