Tools > Options > Advanced > Network tab
try increasing to something like 200MB (mine was at 50MB - probably default)
I tried testing it a little but I have broadband so it's difficult to tell, unless I found a very large video.
You could also try the MozillaZine Forums for info.
Hey CNet members,
When I go on flash sites with Internet Explorer, such as YouTube, and I view a clip, and I go back to the page, it doesn't start from scratch, its in the temporary internet files,
But when I use Firefox my default internet browser, it seems to re-download the whole thing from scratch each time,
Is there a plugin or a setting, in which I can fix this thing,
Hope to hear some feedback,
Thanks in advance,