I had Firefox 51.x (I am not certain if it was 51.0.1 51.0.2 or 51.0.3) installed on a system using Windows 10 Professional 64-bit. I figured since it was several month outdated I would backup my bookmarks, uninstall Firefox, delete the profile I had for Firefox 51, checked BOTH C:\Program Files AND C:\Program Files (x86) directories on the hard drive to make sure it was not there, then I pressed Windows + R to open Run and then typed in the box %AppData% and then deleted the profile I had for Firefox 51 Stable, download the full version of 57.0.2 64-bit (English (US) 37MB from Firefox website), and installed it. I tried using it on and off since then and it has been IMPOSSIBLE to use. If I have no more than 3 tabs open at any given time it runs slower than snails. Any action you do on a website (e.g. Scrolling on the page/clicking in a search box so the cursor can appear so I can type something and when the cursor does appear start typing something and not seeing anything show in the box and then not knowing if you have typed anything in there at all and if I did them wonder if I made any typos when typing in the box/switching between tabs) took FOREVER to be done. I got things done faster in Internet Explorer 11 (which I will use if I have to) than I could with this version of Firefox and this is on the stable channel of it. I did not have this issue when using Firefox 51 32-bit on the stable channel. Also last week when I noticed these issues I downloaded the full version of Firefox 58 from the Beta Channel from Firefox (English (US) approximately 39MB). Then I installed it to a different directory in C:\Program Files in Windows so Firefox Stable and Beta would be in different installation directories and would not interfere with each other. Then I went to the icon on the desktop for Firefox Stable, right-clicked on it, clicked on properties, where it had "C:\Program Files\Mozilla Firefox\firefox.exe" I clicked at the end of it and pressed the space bar ONCE, then put in -P, then clicked on apply, and then clicked on OK. Then I double-clicked on the icon for Firefox Stable and the profile manager opened. Then I chose the option to create a new profile and named it Stable so I would know it's for the Stable release of Firefox. After I got into Firefox 57.0.2 (Stable channel) I closed it and then then looked at all the processes in Task Manager to make sure Firefox was no longer running. Then I went to the icon on the desktop for Firefox Beta, right-clicked on it, clicked on properties, where it had "C:\Program Files\Mozilla Firefox Beta\firefox.exe" I clicked at the end of it and pressed the space bar ONCE, then put in -P, then clicked on apply, and then clicked on OK. Then I double-clicked on the icon for Firefox Beta and the profile manager opened. Then I chose the option to create a new profile and named it Beta so I would know it's for the Beta release of Firefox. Then I went on into Firefox Beta and started using it. The things I was trying to do in the 3 tabs in Firefox stable release I tried to do in Firefox Beta using 3 tabs there. Firefox Beta was only a TAD faster than the stable version, but not by much. I had the same issues with Beta that I did with Firefox Stable. Then for fun I went to Firefox again and went to their Develop (Alpha) channel to download it (English (US) approximately 39.3MB). Then I went to install it making certain to install it in a different directory than the other 2 Firefox channels I have installed. After that I found the icon on the desktop for Firefox Developer, right-clicked on it, clicked on properties, where it had "C:\Program Files\Mozilla Firefox Developer\firefox.exe" I clicked at the end of it and pressed the space bar ONCE, then put in -P, then clicked on apply, and then clicked on OK. Then I double-clicked on the icon for Firefox Developer and the profile manager opened. Then I chose the option to create a new profile and named it Developer so I would know it's for the Developer release of Firefox. Then I went on into Firefox Developer and started using it. The things I was trying to do in the 3 tabs at the same time in Firefox Stable I tried doing those same things in 3 different tabs at the same time in Firefox Developer. That channel worked how Firefox Stable is supposed to work. I had no issues using Firefox Developer. I kept those 3 tabs opened and went on to something else while still n Firefox Developer and the next thing I know I not only had the 3 tabs opened when trying to recreate what I was doing in Firefox Stable but I also had 4 more tabs opened for a total of 7 opened tabs. I could go from one tab to another (did matter if I wanted the tab on either side of the one I was currently on or a tab that was 3-4 tabs away from the one I was currently on) in the amount of time it should take to switch between tabs. The speed that Firefox Developer was running is the speed that Firefox Stable should be running and Stable AND Beta is NOT doing this. I have to go to Developer (which is basically Alpha) to get this speed. There are certain things I need to do in a web browser (i.e. pay bills, anything that I need a secure connection for, etc.) and I need to do that with Stable not Developer since Developer is not a finished/final release of the browser.

Do I need to go back to Firefox 57 32-bit or Firefox 52 ESR to get a working version of Firefox.