Using 8.0a1 (2011-07-28) I've observed that recent builds are much worse in memory management than less recent ones (having just about 5 open tabs used 500 - 600 MB) and decided to conduct a test. I created a fresh profile with disabled hardware acceleration. I had initial tab open and kept opening a new one with Gmail or gizmag.com and closing it. Below are my results. (I waited for things to settle down as long as seemed reasonable.) Started with 123 MB. Opened Gmail -> 178 MB. Closed Gmail -> 162 MB Opened Gmail -> 191 MB Closed Gmail -> 172 MB Opened Gmail -> 197 MB Closed Gmail -> 161 MB Opened gizmag.com and looked at a couple of articles and watch an image gallery there -> 193 MB Closed gizmag.com -> 180 MB

I guess you at least have to document the output of about:memory to be able to draw any conclusions from your test.

Especially you need to hit "minimize memory use" in about:memory a few times - you need to force it to garbage-collect (that's part of the cause of the size wandering up and down). If it still looks like a leak, include a attachment with copies of the about:memory data (preferably the verbose option); after each iteration (with several hits of minimize) would be best.

Things have become much better in the last several days.

Still bad usage of RAM. I am attaching files with data from about:memory. I've pressed the buttons to GC (and the others) several times. Using 9.0a1 (2011-08-30)

the tab, not tap

Roman R. there is still another bug (bug 323362) for Yahoo mail. Please test the links you wrote in the report, otherwise mark this as duplicate of the other bug.

Marco, that bug is for a very old version of Firefox and an old version of Yahoo mail, so my issue can't be a duplicate of that one and should stand on its own.

As the problem with Yahoo Mail, as you pointed out, is still there, I've marked the other bug as duplicate of this, because they are the same. Do you still have problems with GMail or gizmag.com?

This isn't a clear problem. The results look very much as expected.