@goldengate415
In the settings of the Pagespeed/Above the Fold plugin, when you are on the tab CriticalCSS, then halfway the page you see:

Extract Full CSS
For the creation of Critical Path CSS you need the full CSS of a page. This tool allows you to extract the full CSS from any url and optionally to select the specific CSS files you want to extract.
You can quickly output the full CSS of any url by adding the query string ?extract-css=0eae7250104aba6e53dcec8cb3d6c00e&output=print.

At that point you can download your complete css of your website.

@CurlyHost
You should start a Chrome Webbrowser, press Ctrl-Shift-I to open the developer tools.
With the plugin disabled and your browser-cache cleared, open your website and check in Chrome-dev-tools on the network-tab how fast you site was loaded. Notice the number of files that are downloaded from the webserver.
Now enable the plugin, clear your browser cache and open your website again and check the network speed in the Chrome-dev-tools. The number of files is decreased, and also the time to load the total number of files is less.
So there should be a difference, less files should be downloaded because more css is rewritten as inline style.
Of course you should know that Google also uses the loading-time of your website to rank your website, although this is only small part of your ranking.

Hi all,

I agree with Rikard that a Google-tool decides for you if your site has a good user-experience or not.

I mentioned that I will update the experiences I have done on my website.
Right now I have 93/100 on Mobile and 97/100 on Desktop via the https://developers.google.com/speed/pagespeed/insights website. The last few percentages are javascript-optimization items, but some js-optimization plugins I tried broke the website-functionality.

Below are the settings I made to get to this score. Of course it took a lot of time trying, testing and reading to get to this point. Don’t be disappointed if it does not work for you, those are my settings for my website and things will depend on which other plugins you have deployed on your site, that might have other blocking css or js.

What I did:
Installing
Install the plugin Autoptimize.
Install the plugin Comet Cache.
Install the plugin Above the Fold Optimization.
Activate them all.
So far the easy part ;)

Go to Comet cache settings :
(only important settings below)

Enable: yes
Automatic Cache clearing: set them all to yes
Cache Directory: any writable directory on you hosting server; keep default cache/comet-cache
Client side cache: yes
Get requests: no

Above the fold Optimization (Pagespeed)
Critical CSS:
Critical Path CSS: <get the full CSS, and put it into an online CSS-optimizer and paste it here>
Enable Condition CSS: no

CSS:

Optimize CSS Delivery: yes
Enhanced loadCSS: yes
Position: Footer
Ignore List: <empty>
Remove List: print.css
Optimize Web Fonts: yes
webfont.js Load Method: async
Load Position: footer
WebFontConfig: <default>
Google Web Fonts: Lato:300,400,700:latin <and your other fonts that you use from Google, each on one line>
Exclude List: <empty>

Javascript:

Optimize Javascript Loading: yes
Script Loader: little-loader + HTML5 Web Worker <for this setting to enable, you need also to enable Proxy Scripts on the Proxy Tab>
Position: header
Ignore List: <empty>
Remove List: <empty>
Force Async: yes
Async Disabled List: <open the avia.js in a text-editor, find the function for Smooth Scrolling (starts at line 713, ends at 853), copy and paste it here>
Abide dependencies: no
JQuery Stub: yes
Lazy Load Scripts: no

Autoptimize
Show Advanced Settings
HTML Options

Optimize HTML Code: yes
Keep HTML comments: no

Javascript Options

Optimize JavaScript Code: no

CSS Options

Optimize CSS Code: yes
Generate data: URIs for images: no
Remove Google Fonts: no
Also aggregate inline CSS: no
Inline and Defer CSS: yes
<paste necessary/critical CSS here that you acquired in the previous step>
Exclude CSS from Autoptimize: admin-bar.min.css, dashicons.min.css, print.css

• This reply was modified 7 years, 11 months ago by Arnold. Reason: formatted this post a bit

To add some useful information to this thread: I am using the above-the-fold-optimization plugin in WordPress. At the moment I have succeeded to get all critical-css into html-inline css, and am nearly done with the javascript.
To get a non-blocking html-page you need to have all critical css and js to be inline in your html page (thus not to be called from an external .css or .js file) and have the inline javascript call the remainder of the css and js. This can all be done by the plugin I mentioned.
Right now I have 79/100 on desktop and 69/100 on mobile, and hope to have a better score when I find the blocking javascript function.
I keep you posted with my progress.
BR, Arnold