I have tested your website with different browsers and it is the same loading time for me. Please try starting Firefox in Safe mode to see if the problem is gone.

If Firefox is open, you can restart in Firefox Safe Mode from the Help menu:

   Click the menu button New Fx Menu , click Help Help-29 and select Restart with Add-ons Disabled.

Thanks to be a part of discussion, Let me follow your instructions. Then i'll let you know. Well, i was using old version of mozilla, after updating, i'm still facing same issue. On the other hand, i used portable firefox and my site is loading fine there. I'm not sure what's going on installed mozilla and why this is happening.

You might want to start here and fix your code. Code issues can make pages load slower on different browsers. W3C ( Markup Validation Service ) can help you with the issues as they are the governing authority. https://validator.w3.org/ There is also a one for CSS https://jigsaw.w3.org/css-validator/ Your errors for your index page are here https://validator.w3.org/nu/?doc=http%3A%2F%2Fdashcambox.com%2F Your CSS https://jigsaw.w3.org/css-validator/validator?uri=http%3A%2F%2Fdashcambox.com%2F&profile=css3&usermedium=all&warning=1&vextwarning=&lang=en Suggest fixing the errors to see if that speeds anything up for you.

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