Browser memory usage - the good, the bad, and the down right ugly!

So how much memory do modern web browsers consume when pushed hard? This was the question prompted by my Firefox 3.0 a memory hog? post yesterday.

So how do the browsers stack up against each other?

The Test

I took six identical VMware virtual PCs, running Windows Vista Ultimate SP1 32-bit. The systems were given a meager 512Mb of RAM. We then took the browsers for a one hour browsing session, visiting some of the Internet’s best “hot sheets” websites and loading up 30 tabs for each browser. I also accessed and made use of several Google services (such as Gmail and Google Analytics).

Note: I tried to keep the browsing as similar as possible for all the browsers.

The Results

Here are the results:

So, we have the good (Opera 9.27 and Firefox 3.0 RC2), the bad (Opera 9.50B2, Safari 3.1.1, and Internet Explorer 8 Beta 1), and the ugly (Internet Explorer 7).

What's interesting is that if I were to list the browsers in order of sluggishness when running with 30 tabs open, the order would be the same as for the memory usage, with IE7 being the most sluggish and Firefox 3.0 RC2 and Opera 9.27 being the most responsive.

Thoughts?