frontpage - 12:58 pm on Jan 5, 2011 (gmt 0)
I am using Firefox 3.6.13 and it runs fine. I think with a modern computer and the minimum requirement of RAM, the majority of users will not have any problem.
In fact, I built a Franken-computer recently of parts from 1997 with only 512mb of RAM and a Pentium processor. Installed Ubuntu and Firefox runs fine.