My browser crashes about once per day. I usually have about 40-50 tabs but at times when I increase the memory usage, the program crashes. The session usually recovers but sometimes it stops saving a hour before due to memory issues. The system has 6 GB of memory and haven't had this problem until recently. The memory usage is around 80 percent and Firefox totals more than half of the percent. When I open Firefox again, I get a AVG notice that shows high memory usage of over 2 GB for the Firefox application and that it would be best to restart the program.
Firefox obviously is having memory problems for some reason. The AVG reports often can usually be ignored, although in this case they seem valid.
As the Crash Reports do not point to an immediate solution the first troubleshooting step is to run Firefox in safemode and with all plugins disabled, that may either prevent crashes or provide a more useful set of Crash Reports.
Are you able to test in Firefox's safemode and with all plugin disabled as I suggested in my last post. Then post Crash IDs whilst Firefox is like that.
If Firefox is not crashing in its Safe Mode with plugins disabled then one of the plugins or one of your extensions could be the trigger of the crashes or it could be something else safe mode changes such as hardware acceleration.
I am not too sure how Windows handles memory. Firefox on Windows is only a 32bit application. So even though you are on a 64bit machine with 8GB that may limit Firefox to 2GB before paging. Anyhow I would not expect Firefox necessarily to use 2GB never mind crash with High Memory with only 25 tabs, especially with no plugins enabled. I think Firefox may be expected to slowdown more gracefully as it pages rather than crash.