Firefox too heavy?

[jsmoke]

Several tabs open, watching a YT video and it can grind PC to a halt after 15 mins or so, it's like going back to the mid 90's, is this just me, any tips or tricks?

 

[jsmoke]

Firefox keeps changing the search engine to 'default search' which happens is Bing. I have deleted all other search engines including default search in FF options and it then useswith google(if I select some text and right click/search etc) however it soon changes back to deafult/Bing. Anyone have this issue?

 

[jsmoke]

TIP: Turns out if you disable hardware acceleration and increase the process limit then much faster.