There’s a very cool post on the Pavlov.net blog, Firefox 3 Memory Usage.
There’s a lot in the post. Reducing Memory fragmentation, the Cycle collector, how image data is stored .. and lots more.
Down towards the bottom there’s a graph showing memory Megabytes over Time for IE7, Firefox 2 and Firefox 3. It’s a bit freaky. Firefox 3 has such a dramatic memory reduction. You would expect some benefit with a new version, but this is phenomenal.
What is also a bit weird is the continual increase in memory (relatively) for IE7. Someone at Microsoft is feverishly coming up with a different graph. Or trying to reduce memory in IE8. Or perhaps they don’t care.