If I have more than a handful of tabs open in Chrome then Chrome starts using significantly more than a GB of RAM (in total, across all the separate Chrome processes), while I've currently got a Firefox session that has been open for more than a week, with 30+ tabs, and is using just under 1 GB.
How are you adding together the Chrome processes? Often when you look at the memory usage of a process, it'll incude all the shared libraries it's using. So if you add together multiple processes, you'll multiply the memory used by that shared library by the number of processes you're adding, even though that memory is, well, shared.
Oh. Hadn't realised that, thanks for the info. :) (I am doing it naively, just from the output of ps, so your point applies. Is there an Chrome equivalent for Firefox's about:memory?)
Even so, with many tabs open, my computer hits swap far more under Chrome than Firefox.
Edit: Ah, yep, answered my own question: about:memory works in Chrome too. Using that, I've got Chrome at 360 MB with 5 tabs and 2 extensions, while Firefox is at 900 with 30+ loaded tabs and ~20 extensions.
If I have more than a handful of tabs open in Chrome then Chrome starts using significantly more than a GB of RAM (in total, across all the separate Chrome processes), while I've currently got a Firefox session that has been open for more than a week, with 30+ tabs, and is using just under 1 GB.