if you go to download.com they will have different versions of firefox (that's where I went when I decided to venture into testing 1.5 in it's beta & rc stages).
I don't notice it much, but it is more likely to crash on me when you consider the fact that that I have my pc overclocked, & overclocking can account for some apps crashing (also dependent on the vcore of a cpu, or the voltage, fsb speed & or multipler you put your cpu at, same goes for memory in simlar aspects).
I would suggest running Superpi and see if you do crash, even if your running you pc on stock speeds, or maybe there could be a error in your ram (most generic sticks get like that too if you bought some cheap memory).
One thing for sure though is firefox will always crash when the so called "quality feed back agent pops up". More like "quality pc crashing" to me atleast. Just do a reinstall and untick the feed back agent or disable it, that should stop some of the crashes
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