If 70+ "average modern" webpages are open, then I do not see how these could possibly add up to less than 1 GB. I would think that some things do load in the background, before the tab is viewed.

If your free (currently unused) system RAM is 1GB or less, then you could have a lot of problems.

How much free RAM do you have on reserve?

I have 4gb ram on this system, but it does the same on my macbook pro i7 16gb ram 500gb SSD, which makes no sense at all?

Thanks for any help you can offer.

Does Firefox do this when no other programs are open?

When no other programs are open...

• How much free RAM do you have on reserve in each case? This is the headroom, the part not in use nor the total system RAM. If there is not enough free RAM, then your PC could possibly even crash.
• What percent of full processing rate are your processors at? I would think that RAM is not the only thing strained here. It also takes processing power.

[Edit: I had incorrectly stated "available", but meant "free". Fixed.]

Hi, I'll reply tomorrow as I'm off to bed now and my system is off, I need to check on that information for you.

Thanks for all your help so far.

Wayne :)

Ok, sounds good. When you get back, would you be willing to reproduce the following, but with your normal 40+ tabs open?

My system with 3 forum tabs open plus Library, my Task Manager program on Win7Pro says:

Physical Memory (i.e. RAM)

• Total = 16 GB
• Free = 13 GB
• In use = 13%.
• Firefox process = 363 MB.

CPU (i.e. processor)

• In use = 0% - 4%.
• Firefox process = 0%.

Task Manager can be opened via <ctrl><alt><delete>. Tabs of interest are "Processes" and "Performance".

Hi, ok so my task manager in Win7Pro reads as follows:

Physical Memory

   Total = 4 GB
   Free =  1.5GB
   In use = 62%.
   Firefox process = 525 MB. 

CPU

   In use = 0% - 2%.
   Firefox process = 1%. 

This after a fresh boot and nothing else running. After a few hours or less of use, it will start to significantly deteriorate and require a restart.

Many thanks.

Are most of the tabs newly opened during the current session, or restored from earlier sessions?

By default, Firefox minimizes memory use for restored tabs by not fetching their content until you activate them. Are you using the default setting -- only the last active tab in each window loads -- or do you have Firefox set to reload every tab?

Some sites use a ton of RAM in Firefox, particularly sites like Facebook and Twitter that use an endless loading approach to keep adding more content to the same page. Fortunately, most sites do not do that.

Over the years, add-on developers have created some ingenious tools to reduce the memory usage of inactive tabs. For example, after a time, they may free the memory of the tab content while keeping the tab open. Having read about several, I actually have never tried any of them myself. If you do a search on the Add-ons site, please check the reviews carefully to see whether users are reporting compatibility issues with the latest versions of Firefox

Same prob. with a lot of tabs open, it dogs down to where I dont see what Im typing for 5 to 30 sec. Or more, screen keeps dimming even at startup with 1 window and a tab or 2, about the only response that is EVEN timely is clicking between windows - that still takes a few seconds. Also, restore (if it works at all) brings back some of windows usually 1 with all tabs, rest with blank tabs - If Im reeaaly lucky I will get all back.

(session manager doesnt always bring back tabs or show up - even though set to) especially if I force quit ( I dont like waiting 10+ min. for shutdown)

Ubuntu 16.04, CPU: 2.33 ghz, 6 G ram no other progs running

I dont know this chopped off the top of my question, but I'll try to put it back (all part of how this is really screwing with me)

rather than edit above (risk) theres a odd 'progress bar" looking line across my post even after restarting computer - I still have to wait a long time - 10 - 40 sec. to see what Ive typed

Update, a few days later, Still Sloow sometimes totally nonresponsive - system monitor show ~10% CPU usage, mem. ~4 of 6 gigs, other times its all maxed out ... not much diff. from user side.