In this Google PageSpeed Experiment, we’re testing W3 Total Cache’s Delay Scripts tool to understand it’s impact on website performance.
We want to find out exactly how this feature helps enhance page load times so we have set up two websites, a control website and an experimental website.
Control Website
For our control website, we created a brand new WordPress installation. In this experiment we’re using the Twenty Twenty-Four WordPress theme, a live chat plugin, and three active code snippets that pull in a weather widget, custom chart and a Google Calendar.
The purpose of adding these plugins and snippets is to generate different JS files on the site. This will help us test the “Delay Scripts” tool when we set up our “Experimental Website”.
Control Website: https://wordpress-speed-test.com/042624-site1/
Experimental Website
We duplicated our Control Website on to a new sub-folder to create a new Experimental Website that mirrors the original one.
We also installed W3 Total Cache Pro, enabled the Delay Scripts tool and used it to delay these four scripts for 10 seconds:
– event-calendar
– https://www.gstatic.com/charts/loader.js
– livechatinc.com
– weatherwidget.io
Experimental Website: https://wordpress-speed-test.com/042624-site2/
-627.5
milliseconds
In this test, using the Delay Scripts feature decreased the Time Third-Party Code Blocked The Main Thread for mobile by -627.5 ms on mobile devices and -42.5 ms for desktop in the Google PageSpeed score results! Read the documentation to learn how to use the Delay Scripts tool.
Upgrade to W3 Total Cache Pro and improve your PageSpeed Scores today!
Desktop
Mobile
Performance
Performance score
| Standard site |
W3TC Optimized | Difference |
| 95 |
97.5 |
+2.5
|
+2.63%
|
|
|
|
Points per Metrics
First Contentful Paint
| Standard site |
W3TC Optimized | Difference |
| 10 points |
10 points |
0 points
|
0%
|
| No change. |
Largest Contentful Paint
| Standard site |
W3TC Optimized | Difference |
| 21 points |
23 points |
+2 points
|
+9.52%
|
|
|
|
Total Blocking Time
| Standard site |
W3TC Optimized | Difference |
| 30 points |
30 points |
0 points
|
0%
|
| No change. |
Cumulative Layout Shift
| Standard site |
W3TC Optimized | Difference |
| 25 points |
25 points |
0 points
|
0%
|
| No change. |
Speed Index
| Standard site |
W3TC Optimized | Difference |
| 9 points |
9.75 points |
+0.75 points
|
+8.33%
|
|
|
|
Metrics
First Contentful Paint
| Standard site |
W3TC Optimized | Difference |
| 0.6 s |
0.58 s |
-0.03 s
|
-4.17%
|
|
|
|
Largest Contentful Paint
| Standard site |
W3TC Optimized | Difference |
| 1.38 s |
1.1 s |
-0.28 s
|
-20%
|
|
|
|
Total Blocking Time
| Standard site |
W3TC Optimized | Difference |
| 12.5 ms |
2.5 ms |
-10 ms
|
-80%
|
|
|
|
Cumulative Layout Shift
| Standard site |
W3TC Optimized | Difference |
| 0.01 |
0 |
-0.01
|
-92.59%
|
|
|
|
Speed Index
| Standard site |
W3TC Optimized | Difference |
| 1.28 s |
0.98 s |
-0.3 s
|
-23.53%
|
|
|
|
Diagnostics
# of Facade alternatives available
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Largest Contentful Paint element
| Standard site |
W3TC Optimized | Difference |
| 1365 ms |
1105 ms |
-260 ms
|
-19.05%
|
|
|
|
Potential savings from render-blocking resources
| Standard site |
W3TC Optimized | Difference |
| 242.5 ms |
155 ms |
-87.5 ms
|
-36.08%
|
|
|
|
Potential savings by serving images in next-gen format
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Time third-party code blocked the main thread for
| Standard site |
W3TC Optimized | Difference |
| 45 ms |
2.5 ms |
-42.5 ms
|
-94.44%
|
|
|
|
Potential savings from unused CSS
| Standard site |
W3TC Optimized | Difference |
| 13 KiB |
13 KiB |
0 KiB
|
0%
|
| No change. |
Potential savings from unused JavaScript
| Standard site |
W3TC Optimized | Difference |
| 294.5 KiB |
96.75 KiB |
-197.75 KiB
|
-67.15%
|
|
|
|
Potential savings if Minifying CSS
| Standard site |
W3TC Optimized | Difference |
| 3 KiB |
3 KiB |
0 KiB
|
0%
|
| No change. |
# of static assets without an effecient cache policy
| Standard site |
W3TC Optimized | Difference |
| 31 |
15 |
-16
|
-51.61%
|
|
|
|
JavaScript execution time
| Standard site |
W3TC Optimized | Difference |
| 0.33 s |
0.1 s |
-0.23 s
|
-69.23%
|
|
|
|
Main-thread work
| Standard site |
W3TC Optimized | Difference |
| 0.9 |
0.28 |
-0.63
|
-69.44%
|
|
|
|
# of long main-thread tasks
| Standard site |
W3TC Optimized | Difference |
| 2.33 |
1 |
-1.33
|
-57.14%
|
|
|
|
Initial server response time
| Standard site |
W3TC Optimized | Difference |
| 192.5 ms |
205 ms |
+12.5 ms
|
+6.49%
|
|
|
|
# of large layout shifts
| Standard site |
W3TC Optimized | Difference |
| 0 |
1 |
1
|
|
|
|
# of user timings
| Standard site |
W3TC Optimized |
| 0 |
Passed audit |
# of animations found
| Standard site |
W3TC Optimized |
| 0 |
Passed audit |
Network payload
| Standard site |
W3TC Optimized | Difference |
| 1305.5 KiB |
762 KiB |
-543.5 KiB
|
-41.63%
|
|
|
|
DOM size
| Standard site |
W3TC Optimized | Difference |
| 593 |
150 |
-443
|
-74.7%
|
|
|
|
# of chains found
| Standard site |
W3TC Optimized | Difference |
| 19 |
16 |
-3
|
-15.79%
|
|
|
|
Defer offscreen images
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Minify JavaScript
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Properly size images
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Efficiently encode images
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Enable text compression
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Preconnect to required origins
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Preload key requests
| Standard site |
W3TC Optimized | Difference |
| 0 |
0 |
0
|
| No change. |
Preload Largest Contentful Paint image
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Avoid multiple page redirects
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Use video formats for animated content
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Remove duplicate modules in JavaScript bundles
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Avoid serving legacy JavaScript to modern browsers
| Standard site |
W3TC Optimized | Difference |
| 0 |
0 |
0
|
| No change. |
Largest Contentful Paint image was not lazily loaded
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Avoids document.write()
| Standard site |
W3TC Optimized | Difference |
| 0 |
0 |
0
|
| No change. |
Image elements have explicit width and height
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Has a <meta name="viewport"> tag with width or initial-scale
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Uses passive listeners to improve scrolling performance
| Standard site |
W3TC Optimized |
| 0 |
Passed audit |
All text remains visible during webfont loads
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Performance
Performance score
| Standard site |
W3TC Optimized | Difference |
| 56.75 |
74.75 |
+18
|
+31.72%
|
|
|
|
Points per Metrics
First Contentful Paint
| Standard site |
W3TC Optimized | Difference |
| 6.5 points |
7 points |
+0.5 points
|
+7.69%
|
|
|
|
Largest Contentful Paint
| Standard site |
W3TC Optimized | Difference |
| 4.5 points |
6.5 points |
+2 points
|
+44.44%
|
|
|
|
Total Blocking Time
| Standard site |
W3TC Optimized | Difference |
| 13.75 points |
26.25 points |
+12.5 points
|
+90.91%
|
|
|
|
Cumulative Layout Shift
| Standard site |
W3TC Optimized | Difference |
| 24.5 points |
25 points |
+0.5 points
|
+2.04%
|
|
|
|
Speed Index
| Standard site |
W3TC Optimized | Difference |
| 8 points |
10 points |
+2 points
|
+25%
|
|
|
|
Metrics
First Contentful Paint
| Standard site |
W3TC Optimized | Difference |
| 2.65 s |
2.35 s |
-0.3 s
|
-11.32%
|
|
|
|
Largest Contentful Paint
| Standard site |
W3TC Optimized | Difference |
| 5.8 s |
5.3 s |
-0.5 s
|
-8.62%
|
|
|
|
Total Blocking Time
| Standard site |
W3TC Optimized | Difference |
| 432.75 ms |
212.5 ms |
-220.25 ms
|
-50.9%
|
|
|
|
Cumulative Layout Shift
| Standard site |
W3TC Optimized | Difference |
| 0.04 |
0 |
-0.04
|
-100%
|
|
|
|
Speed Index
| Standard site |
W3TC Optimized | Difference |
| 4.13 s |
2.6 s |
-1.53 s
|
-36.97%
|
|
|
|
Diagnostics
# of Facade alternatives available
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Largest Contentful Paint element
| Standard site |
W3TC Optimized | Difference |
| 5800 ms |
5277.5 ms |
-522.5 ms
|
-9.01%
|
|
|
|
Potential savings from render-blocking resources
| Standard site |
W3TC Optimized | Difference |
| 1202.5 ms |
937.5 ms |
-265 ms
|
-22.04%
|
|
|
|
Potential savings by serving images in next-gen format
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Time third-party code blocked the main thread for
| Standard site |
W3TC Optimized | Difference |
| 825 ms |
197.5 ms |
-627.5 ms
|
-76.06%
|
|
|
|
Potential savings from unused CSS
| Standard site |
W3TC Optimized | Difference |
| 13 KiB |
13 KiB |
0 KiB
|
0%
|
| No change. |
Potential savings from unused JavaScript
| Standard site |
W3TC Optimized | Difference |
| 295 KiB |
96.75 KiB |
-198.25 KiB
|
-67.2%
|
|
|
|
Potential savings if Minifying CSS
| Standard site |
W3TC Optimized | Difference |
| 3 KiB |
3 KiB |
0 KiB
|
0%
|
| No change. |
# of static assets without an effecient cache policy
| Standard site |
W3TC Optimized | Difference |
| 31 |
15.25 |
-15.75
|
-50.81%
|
|
|
|
JavaScript execution time
| Standard site |
W3TC Optimized | Difference |
| 1.95 s |
0.58 s |
-1.38 s
|
-70.51%
|
|
|
|
Main-thread work
| Standard site |
W3TC Optimized | Difference |
| 4.15 |
1.23 |
-2.93
|
-70.48%
|
|
|
|
# of long main-thread tasks
| Standard site |
W3TC Optimized | Difference |
| 10.25 |
7.25 |
-3
|
-29.27%
|
|
|
|
Initial server response time
| Standard site |
W3TC Optimized | Difference |
| 170 ms |
175 ms |
+5 ms
|
+2.94%
|
|
|
|
# of large layout shifts
| Standard site |
W3TC Optimized |
| 0 |
Passed audit |
# of user timings
| Standard site |
W3TC Optimized | Difference |
| 0 |
101 |
101
|
|
|
|
# of animations found
| Standard site |
W3TC Optimized |
| 0 |
Passed audit |
Network payload
| Standard site |
W3TC Optimized | Difference |
| 1306.5 KiB |
762.75 KiB |
-543.75 KiB
|
-41.62%
|
|
|
|
DOM size
| Standard site |
W3TC Optimized | Difference |
| 593 |
150 |
-443
|
-74.7%
|
|
|
|
# of chains found
| Standard site |
W3TC Optimized | Difference |
| 19 |
16 |
-3
|
-15.79%
|
|
|
|
Defer offscreen images
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Minify JavaScript
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Properly size images
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Efficiently encode images
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Enable text compression
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Preconnect to required origins
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Preload key requests
| Standard site |
W3TC Optimized | Difference |
| 0 |
0 |
0
|
| No change. |
Preload Largest Contentful Paint image
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Avoid multiple page redirects
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Use video formats for animated content
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Remove duplicate modules in JavaScript bundles
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Avoid serving legacy JavaScript to modern browsers
| Standard site |
W3TC Optimized | Difference |
| 0 |
0 |
0
|
| No change. |
Largest Contentful Paint image was not lazily loaded
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Avoids document.write()
| Standard site |
W3TC Optimized | Difference |
| 0 |
0 |
0
|
| No change. |
Image elements have explicit width and height
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Has a <meta name="viewport"> tag with width or initial-scale
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
Uses passive listeners to improve scrolling performance
| Standard site |
W3TC Optimized |
| 0 |
Passed audit |
All text remains visible during webfont loads
| Standard site |
W3TC Optimized |
| Passed audit |
Passed audit |
+18
Points
In this test, using the Delay Scripts feature added 2.5 points on desktop and 18 points for mobile devices to the Google PageSpeed Performance score! Read the documentation to learn how to use the Delay Scripts tool.
Upgrade to W3 Total Cache Pro and improve your PageSpeed Scores today!
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