Why do browsers use so much memory? [closed]

Question

Firefox with 18 tabs open = 1.34GB of memory (~75MB/tab).

Got a reply on twitter from another local developer mentioning his Chrome instance was using ~82MB/tab.

What causes web browsers to consume that much memory?

Answer 1

To make it more crash-resistant, Chrome spawn many copies of itself as full-fledged processes instead of simply using multi-threading. This clearly eats more memory (less things can be shared). Chrome puts the plugins in separate processes (so that a crash of Flash won't bring down the whole browser)... Other memory consumed... And so on.