Does anyone have this issue were firefox becomes slow if left open for a long time. In my case after a couple of weeks rendering becomes slow and when I use youtube for example if is laggy, just trying to change volume taka few second to show the volume bar. It also happens to my laptop at work. I have around 30 tabs open.
I test firefox vs edge in my pc, both with ublock origin. Firefox noticeably uses more ram than edge which uses same engine as chrome.
Here this person saw the same results as me: https://libreddit.bus-hit.me/r/firefox/comments/18gp19l/ram_usage_in_firefox_vs_edge
Their methodology (and therefore likely yours aswell) is flawed and it was immediately pointed out in that thread too: https://libreddit.bus-hit.me/r/firefox/comments/18gp19l/ram_usage_in_firefox_vs_edge/kd2u2pq/?context=3#kd2u2pq
Measuring the memory "a process" actually "uses" is not trivial.