One of the most significant “improvements” that Mozilla claims to have mitigated is Firefox memory usage, particularly the vanquishing of memory leaks. If you thought it was too good to be true, you were right. Firefox still uses a lot of memory – way too much memory for a web browser.
We like keeping our apps running for a few days (that’s just the way we roll), and because of this, Firefox was using over ~800 MB of memory after about three days. It’s quite normal for Firefox to be sucking up ~100 MB of memory right off the bat.
In a memory leak, you’ll see the memory usage keep increasing the more prolonged the browser is open/in-use, and this is what happens with Firefox.