Safari (macOS Big Sur beta) has memory leaks?

I know a few years ago Safari on macOS was not a memory hog. In fact that’s one of the reasons why I moved from Firefox to Safari on macOS – because I noticed it ate less RAM compared to Firefox. But it looks like things have turned and Safari (at least on macOS Big Sur beta) has memory leaks.

Safari has just 5 tabs open (might have had a maximum of 10 tabs over the course of this session). Firefox has 3 windows with each window having 7-8 tabs! If I close and open Safari the consumption starts low but keeps climbing with each tab I open. It doesn’t go down when the tab is closed so looks like a memory leak.

If I close and reopen Safari with the exact same tabs here’s the reduced consumption:

I am going to ignore this for now in case it’s some Big Sur quirk that will get fixed.