I notice some errors in the info provided for your Video Card. I would suggest re-install or update them. https://support.mozilla.org/en-US/kb/upgrade-graphics-drivers-use-hardware-acceleration

Try this : https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

Think your pushing it with 150 tabs open for days.

See if Multi-Processor Support is turned on. Multi-processor support feature may be disabled depending on your setup (it was for me) - you can check this by launching Firefox, then enter in "about:support" in the address bar; near the bottom, you should see a heading that says: "Multiprocess Windows", then look at the value next to it. If it says "0/1", then that means it's disabled.

To enable multi-processor, go to "about:config" in the address bar, then right click over any one of the headings below, then select New -> Boolean, then enter in "browser.tabs.remote.force-enable", and press enter. On the proceeding window, click on the "True" value, and click OK. Next, close Firefox and go to "about:support" in the address bar to see if "Multiprocess Windows" is enabled - it should be.

Next, close Firefox and reload it. From here on out Firefox should handle heavy loads a lot better. Please also keep in mind that if you had to force the multi-processor support, it may also break some of your add-ons.

Please let us know if this solved your issue or if need further assistance.

I would assume that this is a memory issue where the memory that Firefox uses gets fragmented and the total memory size that is used has increased too much. You can check the memory usage on the about:memory page and try the buttons under "Free Memory".

You can open "about:" pages via the location/address bar

• "about:" is a protocol to access special pages

PKshadow, thanks for the great suggestions. I had to disable 3 add-ons before forcing multiprocess windows worked, Ref Control, User Agent Switcher, and Flashgot. I am also updating my graphics driver, which I too suspected as a likely culprit. It will take a couple days or so to know how much good this does, but I will post an update. Thanks again for your assistance.

cor-el, thanks for the tip on about:memory! That is very handy and I will give it a shot the next time it starts to creep. I will post the results in a couple days. I appreciate the support received here very much. Thanks for your assistance.

I am shooting this back to you to hold onto till know what is going on. Do not reply until it is time to mark this as solved or time to post for further help. This just gets it out of the way. Thanks

I accidentally marked the wrong answer as the solution and I am not sure how to change it , but really the suggestions from Pkshadow and Cor-el were both helpful. I think I had multiple issues going on. Upgrading my graphics driver seems to have cured the locking up and the window jumping to the other screen. Running multiprocess windows seems like it may have helped, but I am unsure how much more access to system resources this really allows. I don't ever see Firefox using more than just over 3 GB of RAM. I would like it to use more since Cor-el's hunch that it was a memory issue seems to be correct as well. Once I load up over a hundred tabs or so switching between tabs shows the spinning wheel in the middle of the window and it takes a moment to render the page. I really would like it to be instant. If there is any way to allow more system resources for Firefox that would be really great, but for now I will call this issue solved since it is running a lot better. Thanks again to both of you for your suggestions.