Firefox now uses multiple processes too. By default Firefox is limited to one UI process and four web content processes. Chrome will use roughly one content pro

Firefox now uses multiple processes too. By default Firefox is limited to one UI process and four web content processes. Chrome will use roughly one content process per tab (though that's an oversimplification). Firefox's choice to use fewer web content processes result in less memory usage, but if a content process crashes you'll have to reload 1/4 of your tabs. Both browsers use threads extensively within each process as well.