How many tabs till firefox crashes?

Yes, Firefox can be a resource hog. Each time you open a tab it takes more and more resources to simultaneously run those tabs, with the amount of resources being consumed depending on the site and the amount/type of content ran on each site, within each tab.

I just did a test myself and with Firefox open and sitting on Google it takes up roughly 120MB of memory. Once I opened a few tabs, those being Tom's Hardware, ESPN, Facebook and Youtube, it went from the initial 120MB to over a little over 300MB being used. If I continued, more memory and resources would be demanded and the computer would get slower and slower.

If she has 15-30 tabs opened, there's a good chance her computer is going to stall and not run properly, if at all. It all depends on how powerful her computer is and what kind of sites she's going to. If she has 20 Google pages open, it's really not a big deal. But if she has a bunch of media intensive pages open, it's going to give you problems.

The speed of the CPU, the amount of memory she has (RAM, not harddrive space), and other programs she's also running has a huge influence as to how many tabs she can run at the same time.

I'm not sure why though she feels the need to have so many tabs open if she can only view one at a time? That's like complaining that your Jetta doesn't go that fast because you have 10,000 lbs of metal in the trunk. Lol. Maybe she needs to start utilizing bookmarks/favorites...

I hope this clears things up for the both of you!  

She generally is running 4 monitors and 4 photoshop projects, skype, yahoo messenger, outlook, firefox, chrome both with 15-30 tabs open on each. She is running a i5-2500k quad core and 16 GB of ram. Considering that adobe memory management is kinda crappy (imho) photoshop actually takes 3 gigs or more in itself. Not to mention her having dreamweaver open on top of that. I've witnessed her firefox crashing myself and had Process explorer open (sysinternals version of task manager) and through all that her i5 was only using 50% or less of her cpu (that thing chugs huh ^^). I think it is just solely to do with firefox itself being overloaded and then it just crashes her system, and it doesn't BSOD or restart or anything it just bogs the system down and closes firefox.

Okay, well she has WAY too much going on at one time.   Lol. And no, I don't think it's Firefox that's the direct result of the crashes, but her overall use of the computer. No offense to her at all, but it just sounds like she's lazy and doesn't like to close out of programs/windows when she's not using them. If she doesn't change the way she uses the computer, it'll continue to crash on her.

And she may have all that going on, but she still only has one mouse and one set of eyes to operate it all with!

...or does she???      

Well an i5 of that caliber should be able to handle it though shouldnt it?

It's not the CPU that's the problem here, but her RAM. The CPU would just cause for the computer to slow down (generally speaking), but eating up all the RAM is what'll cause it to force a reboot. RAM is the memory that's used to store the operating system and applications in real-time. If there's no room left, the computer has to restart to clear everything out.

Edit: And with all that going on, I would say that 16GB would be eaten through. 4 displays + operation system + 4 PS projects + 3-4 applications + 2 browsers with 15-30 tabs per each browser. Yeah, I'd say that would do it. She just needs slow down a bit and it'll take care of itself.

Hmm. I'm not quite sure its the ram either because as I said I witnessed the crashes myself and had hardware monitoring open at the time and she still had a good 5-6 gigs left.

I would switch to chrome only to see it not crash like a boss.
Firefox got worse and worse with updates last decent firefox was 3.5 or so...they are on 18 now? WTH!

True. I think they are doing a 6 week update interval. Each 6 weeks a new version. I've noticed the same thing as well.

Chrome's tabs are run as independent processes so that if one tab crashes or hangs it won't clobber Chrome. Firefox runs all tabs under one process. If one tab misbehaves, firefox will hang or shut down. Mozilla is working on getting their tabs to run as seperate processes, but they aren't there yet.

I also agree with calmstateofmind. She seems to have an aweful lot going on at the same time on that computer. I know there are power users out there, but this sounds extreme.  

Rubbish.

Photoshop - only a problem with memory, but with 16GB it shouldn't be a problem at all.
Skype, yahoo messenger, outlook - lightweight, won't even make the computer blink
Firefox - shouldn't be causing a problem like this. I have over 200 tabs open in Aurora (FF alpha) right now and it's smooth)
Chrome - 30 tabs in Chrome may be a problem, because each uses a separate process. If anything I'd recommend dropping Chrome altogether and trying Firefox alone.

It seems like it's one of those system-specific problems, where one person has a problem that most people don't have. Those problems are sometimes hard to isolate. Sure it may be Firefox, but what in Firefox is causing it? An extension? A script? A plugin? Experiment a little and try to isolate it.

This is quite strange. I'm running firefox with 850tabs opened on a i7 3773k with 16gb ram and bunch of dev programs (I'm a web developer) and I don't have any problems. Yeah from time to time it freezes for a second or two, but that's simply because I have 850 tabs opened...   So I don't believe 15,20 or 30 tabs should be causing the problem. She most probably has a virus or some firefox addons that are causing this problem.

I have a similar problem with Firefox, where having 6-7 pages of PC Gamer opened at the same times cause my PC to BSOD and reboot, referencing a memory problem.

Dell in depth bios memory check lists 0 errors.

Check disk lists 0 bad sectors/problems.

Reduce PCG pages to 3-4? No more BSOD.

4GB of Kingston HyperX RAM@ 667Mhz not even 200MB used with otherwise 30 different tabs open (remember to check the option "do not load until I select the tab", otherwise your browser loads them all at startup).

Crazy part of all this? I had to reformat my comp last time this happened since after BSOD'ing 4-5 times, my comp would automatically totally freeze after about 2 min of loading Win7-64bit. At that time, I wouldn't open Firefox, but all those tabs were still saved in it, and I had no idea.

More crazy part? Loading in Safe Mode resulted no freezing.

Safe Mode probably didn't load Firefox's modules or whatever, so it's like the whole program has a huge memory overflow problem somewhere when facing multiple tabs.

Programmers these days...