Our site's current page speed score is terrible. The exact score varies, but it's between a 2 and an 8 on mobile most times. 

I think the biggest culprits of the slowdown are the large CSS files that IPS loads (framework.css, responsive.css, cjmg.css, mega.css, traditional.css, block.css, cjmg_custom.css, core.css, core_responsive.css, page.css, custom.css) and JS that IPS loads (root_library.js, root_js_lang_1.js, global_core.js, plugins.js, front_menus.js, front.js, global.js, front_app.js, root_map.js). None of those files are related to our theme as far as I know.

Any ideas on how we can reduce the number of these that we have to load? Or at least have some of them wait until after the page has loaded? Is there someone within Invision that has guidance on how to reduce this?

32 minutes ago, GreenSock said:

Any ideas on how we can reduce the number of these that we have to load? Or at least have some of them wait until after the page has loaded? Is there someone within Invision that has guidance on how to reduce this?

Use Cloudflare?

According to the report there's a lot of improvements that can be made server-side such as implementing cache policies for static resources (images, css, js) and also employing compressing techniques for the same files.

If you're using Apache you can use mod_deflate and mod_expires for this. The report estimates this would improve the speed by '8.85s' whatever that means.

You do also have a lot of JS that has been added in your theme, but still adding compression and expires rules should also allow those to perform better.

Open your theme for edit. In Custom menu find

Javascript include location  and select Just before </body> tag.

This will improve the loading speed of the site.
Use appropriate rules for compression and expires time resources in a your htaccess file.

PS. Remove this validation html5 errors

https://validator.w3.org/nu/?doc=https%3A%2F%2Fgreensock.com%2F