I hate these kinds of questions about ram usage. Os developers and browser developers are smarter than you give them credit for. They will do garbage collection when memory becomes tight. You are slowing yourself by clearing ram when you might need it and you still have free ram.
Browsers have sub second back buttons, how much pre-rendered ram space do you think that takes up?
Browsers have sub second back buttons, how much pre-rendered ram space do you think that takes up?