Macbook performance issues with browsers

I have a MacBook Pro from 2013, and I'm having issues in both Chrome and Firefox - both are slowing down to a crawl, and when I check Activity Monitor I have multiple processes (in all the 'tabs' at the top) slowing everything down and triggering the fan. Now I'm guessing each add-on in Firefox and Chrome creates another process called FirefoxCP Web Content, but I also have multiple Adobe CEF Helper and Google Crome Helper. Is there a way to prevent these multiple processes from starting up, without having to go to Activity Monitor and shut things down? Something like a 'basic' setting (like SafeMode) without a massive drain on performance?