How come LinkedIn uses 3.5 GB of RAM?

I saw it first on Chrome, decided to test in Safari. Very similar numbers.

I also compared it with Facebook, with 5 minute deliberate scrolling I got it to consume 650 MB at most, with average being about 400 MB.

Any web developers who can explain the huge discrepancy between LinkedIn and Facebook? It seems like the amount of visual information is almost the same in the feed, yet LinkedIn takes up 5-7x more memory.

I looked up, Facebook uses React and the virtual DOM, whereas LinkedIn uses Ember (never heard of that one before). Is it simply that Facebook is better about dynamically kicking out JavaScript objects when they'ren no longer needed?