Yes, exactly this extension I talk about in another reply - but I don't use Firefox any more because it creates disk load and swaps heavily on a 5400rpm disk, and it locks up while waiting for disk i/o every ten seconds (every tab switch, in essence). Chrome's single-process-per-page model is better, because the OS can do proper swapping.
This is true, the cold startup takes longer in Chrome than in FF. But if you're short on RAM (I usually hit 2-3GB usage without a browser running) and the OS starts swapping when you open tabs (I have ~30-40 open regularly), then the difference appears.
