In this Google PageSpeed Experiment, we’re testing W3 Total Cache’s Remove CSS/JS feature to understand its impact on website performance.
Our goal is to assess how this specific feature influences website speed.
VIDEO
Control Website On our Control website we installed WordPress and the following plugins:
Contact Form 7 Molongui Authorship My Calendar Newsletter Photo Gallery Poll Social Media and Share Icons (Ultimate Social Media) TablePress WordPress Related Posts Thumbnails Control Website: https://wordpress-speed-test.com/03212024-a-before/
Experimental Website With our experimental website, we installed WordPress with the same plugins as our Control Website.
We also installed W3 Total Cache Pro and configured the Remove CSS/JS features.
Experimental Website: https://wordpress-speed-test.com/03212024-a-after/
Experimental Website Changes WordPress plugins often load CSS and JavaScript files, even on pages where they’re unnecessary.
For instance, on our Control Website, the Contact Form 7 plugin adds CSS and JavaScript to the homepage, although no contact form is present.
This extra, unused CSS and JavaScript are called ‘bloat’ and can slow down your website unnecessarily.
To address this, on our Experimental Website, we removed many of these unnecessary CSS and JavaScript files from the homepage.
In the screenshot below, you’ll notice that we’ve removed some scripts and styles from our homepage. For instance, we don’t have a poll running on our homepage, so we don’t need the associated scripts. They’re unnecessary clutter, so we got rid of them.
How the test was run We conducted six tests on each website using the Google PageSpeed test and averaged all the scores.
-34% Potential
In this test, removing unused CSS and JS changed the Potential Savings From Unused JavaScript from 127.5 KiB to 84 KiB. Read the documentation to learn how you can remove unused CSS and JS.
Upgrade to W3 Total Cache Pro and improve your PageSpeed Scores today!
Test results
Desktop Mobile
Performance Performance score Standard site W3TC Optimized Difference 57.17 84.67 +27.5 +48.1%
Points per Metrics First Contentful Paint Standard site W3TC Optimized Difference 0.17 points 8 points +7.83 points +4700%
Largest Contentful Paint Standard site W3TC Optimized Difference 3.17 points 17 points +13.83 points +436.84%
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 22.5 points 22.5 points 0 points 0% No change.
Speed Index Standard site W3TC Optimized Difference 1 points 7.67 points +6.67 points +666.67%
Metrics First Contentful Paint Standard site W3TC Optimized Difference 3.72 s 1.12 s -2.6 s -69.96%
Largest Contentful Paint Standard site W3TC Optimized Difference 4.78 s 1.88 s -2.9 s -60.63%
Total Blocking Time Standard site W3TC Optimized Difference 1.67 ms 0 ms -1.67 ms -100%
Cumulative Layout Shift Standard site W3TC Optimized Difference 0.07 0.07 0 0% No change.
Speed Index Standard site W3TC Optimized Difference 4.58 s 1.73 s -2.85 s -62.18%
Diagnostics Largest Contentful Paint element Standard site W3TC Optimized Difference 4783.33 ms 1895 ms -2888.33 ms -60.38%
Potential savings from render-blocking resources Standard site W3TC Optimized Difference 4891.67 ms 630 ms -4261.67 ms -87.12%
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 0 ms 0 ms 0 ms No change.
Potential savings from unused CSS Standard site W3TC Optimized 59.17 KiB Passed audit
Potential savings from unused JavaScript Standard site W3TC Optimized Difference 127.5 KiB 84 KiB -43.5 KiB -34.12%
Potential savings if Minifying CSS Standard site W3TC Optimized 3 KiB Passed audit
# of static assets without an effecient cache policy Standard site W3TC Optimized Difference 53 20 -33 -62.26%
JavaScript execution time Standard site W3TC Optimized Difference 0 s 0 s 0 s No change.
Main-thread work Standard site W3TC Optimized Difference 0.43 0.28 -0.15 -34.62%
# of long main-thread tasks Standard site W3TC Optimized 1 Passed audit
Initial server response time Standard site W3TC Optimized Difference 396.67 ms 393.33 ms -3.33 ms -0.84%
# of large layout shifts Standard site W3TC Optimized Difference 1.5 1.5 0 0% No change.
# of user timings Standard site W3TC Optimized Passed audit Passed audit
# of animations found Standard site W3TC Optimized Passed audit Passed audit
Network payload Standard site W3TC Optimized Difference 1401.5 KiB 1167.5 KiB -234 KiB -16.7%
DOM size Standard site W3TC Optimized Difference 225 208 -17 -7.56%
# of chains found Standard site W3TC Optimized Difference 50 15 -35 -70%
Defer offscreen images Standard site W3TC Optimized Passed audit Passed audit
Minify JavaScript Standard site W3TC Optimized 3 KiB Passed audit
Properly size images Standard site W3TC Optimized Difference 232.67 KiB 232.67 KiB 0 KiB 0% No change.
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 Passed audit Passed audit
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 Passed audit Passed audit
Image elements have explicit width and height Standard site W3TC Optimized Difference 0 0 0 No change.
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 Passed audit 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 55.17 75 +19.83 +35.95%
Points per Metrics First Contentful Paint Standard site W3TC Optimized Difference 0 points 6.83 points 6.83 points
Largest Contentful Paint Standard site W3TC Optimized Difference 0.17 points 8 points +7.83 points +4700%
Total Blocking Time Standard site W3TC Optimized Difference 29.83 points 29.83 points 0 points 0% No change.
Cumulative Layout Shift Standard site W3TC Optimized Difference 24.5 points 24.33 points -0.17 points -0.68%
Speed Index Standard site W3TC Optimized Difference 0.5 points 5.83 points +5.33 points +1066.67%
Metrics First Contentful Paint Standard site W3TC Optimized Difference 7.75 s 2.45 s -5.3 s -68.39%
Largest Contentful Paint Standard site W3TC Optimized Difference 9.97 s 4.8 s -5.17 s -51.84%
Total Blocking Time Standard site W3TC Optimized Difference 58.33 ms 46.67 ms -11.67 ms -20%
Cumulative Layout Shift Standard site W3TC Optimized Difference 0.04 0.05 +0.01 +33.33%
Speed Index Standard site W3TC Optimized Difference 12.07 s 5.28 s -6.78 s -56.22%
Diagnostics Largest Contentful Paint element Standard site W3TC Optimized Difference 9958.33 ms 4793.33 ms -5165 ms -51.87%
Potential savings from render-blocking resources Standard site W3TC Optimized Difference 9335 ms 1093.33 ms -8241.67 ms -88.29%
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 11.67 ms 10 ms -1.67 ms -14.29%
Potential savings from unused CSS Standard site W3TC Optimized 59.17 KiB Passed audit
Potential savings from unused JavaScript Standard site W3TC Optimized Difference 127.17 KiB 84.17 KiB -43 KiB -33.81%
Potential savings if Minifying CSS Standard site W3TC Optimized 3 KiB Passed audit
# of static assets without an effecient cache policy Standard site W3TC Optimized Difference 53 20 -33 -62.26%
JavaScript execution time Standard site W3TC Optimized Difference 0.35 s 0.32 s -0.03 s -9.52%
Main-thread work Standard site W3TC Optimized Difference 1.4 1.07 -0.33 -23.81%
# of long main-thread tasks Standard site W3TC Optimized Difference 7.67 6.17 -1.5 -19.57%
Initial server response time Standard site W3TC Optimized Difference 643.33 ms 371.67 ms -271.67 ms -42.23%
# of large layout shifts Standard site W3TC Optimized Difference 1 1 0 0% No change.
# of user timings Standard site W3TC Optimized Passed audit Passed audit
# of animations found Standard site W3TC Optimized Passed audit Passed audit
Network payload Standard site W3TC Optimized Difference 1401.17 KiB 1167.5 KiB -233.67 KiB -16.68%
DOM size Standard site W3TC Optimized Difference 225 208 -17 -7.56%
# of chains found Standard site W3TC Optimized Difference 50 15 -35 -70%
Defer offscreen images Standard site W3TC Optimized Passed audit Passed audit
Minify JavaScript Standard site W3TC Optimized 3 KiB Passed audit
Properly size images Standard site W3TC Optimized Difference 304 KiB 304 KiB 0 KiB 0% No change.
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 Passed audit Passed audit
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 Passed audit Passed audit
Image elements have explicit width and height Standard site W3TC Optimized Difference 0 0 0 No change.
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 Passed audit Passed audit
All text remains visible during webfont loads Standard site W3TC Optimized Passed audit Passed audit
