That is a system slowdown because the CPU is overworked.

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

https://support.mozilla.org/en-US/kb/websites-look-wrong-or-appear-differently

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

https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix

https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding

It did not fix it, when I have problems I pull up the task manager to monitor CPU and memory loading and I don't think my problem is due to CPU overloading as the CPU usage has been running under 40% another thing that happens when the cursor starts spinning is the text input is not buffered so when typing you have to watch the screen because if you type during one of these spins the typing is not buffered so you have to make sure every character you type ends up on the screen. Another thing that seems to indicate it is not an overloading issue is that the stoppages are all the same length and usually happen in a constant temporal pattern.

Thanks wade

Start your Computer in safe mode with networking. Then start Firefox. Try Safe websites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

Problem Solved

I finally fixed it, I went through installed programs and removed a number of programs that I could not identify and then rebooted my computer. Since I uninstalled a number of programs and then rebooted I do not know which program was the offending agent, I did not have the time to uninstall one program, reboot check on system and repeat.

That was very good work. Well done.