WP Rocket Speed Test: Before and After Settings, a WordPress Cache Plugin Performance Comparison
We have covered how to set up WP Rocket and its discounted price. After applying the most common settings, we ran a WP Rocket speed test, measuring two things: Chrome DevTools's DOMContentLoaded and Google PageSpeed score.
If you need WP Rocket's setup and pricing information, click the button below.
1️⃣ WP Rocket Speed Test
We ran speed tests in advance, before installing the plugin and after applying each of its options.
For reference, before the WP Rocket speed test the server already had Varnish Cacheinstalled, so there is not much difference.
We measure speed on the Neve theme's Web Agency template, and the measurements were taken in September 2025.
1. Neve theme (free version)
◻️Chrome DevTools speed measurement
We measure speed by DOMContentLoaded in Chrome DevTools. This is before activating WP Rocket.
|
Item |
Value |
|---|---|
|
Average |
47.6 ms |
|
Median |
47 ms |
|
Maximum |
57 ms |
|
Minimum |
39 ms |
|
Standard deviation |
±5.1 ms |
|
Share under 150 ms |
100% (7/7 runs) |
|
Optimization summary |
Good (around 50 ms) |
◻️Google PageSpeed score
![WP Rocket speed test - Google PageSpeed score before activating WP Rocket (2025-09-03) [mobile]](https://uknew.co/storage/2025/09/WP-Rocket-%ED%99%9C%EC%84%B1%ED%99%94-%EC%A0%84-%EA%B5%AC%EA%B8%80-%ED%8E%98%EC%9D%B4%EC%A7%80%EC%8A%A4%ED%94%BC%EB%93%9C-%EC%A0%90%EC%88%982025-09-03%EB%AA%A8%EB%B0%94%EC%9D%BC.png "WP Rocket Speed Test: Before and After Settings, a WordPress Cache Plugin Performance Comparison 2")
![WP Rocket speed test - Google PageSpeed score before activating WP Rocket (2025-09-03) [desktop]](https://uknew.co/storage/2025/09/WP-Rocket-%ED%99%9C%EC%84%B1%ED%99%94-%EC%A0%84-%EA%B5%AC%EA%B8%80-%ED%8E%98%EC%9D%B4%EC%A7%80%EC%8A%A4%ED%94%BC%EB%93%9C-%EC%A0%90%EC%88%982025-09-03%EB%8D%B0%EC%8A%A4%ED%81%AC%ED%83%91.png "WP Rocket Speed Test: Before and After Settings, a WordPress Cache Plugin Performance Comparison 3")
|
Item |
Mobile |
Desktop |
|---|---|---|
|
Score |
92 |
99 |
|
First Contentful Paint |
2.6 s |
0.7 s |
|
Largest Contentful Paint |
2.8 s |
0.7 s |
|
Total Blocking Time |
0 ms |
0 ms |
|
Cumulative Layout Shift |
0.031 |
0.004 |
|
Speed Index |
2.6 s |
1.0 s |
2. Speed test after setting up WP Rocket
Here we check how WP Rocket improved speed after activation.
◻️Chrome DevTools speed measurement after applying the plugin
|
Item |
Value |
|---|---|
|
Average |
43.9 ms |
|
Median |
45 ms |
|
Maximum |
46 ms |
|
Minimum |
39 ms |
|
Standard deviation |
±2.4 ms |
|
Share under 150 ms |
100% (7/7 runs) |
|
Optimization summary |
Good (around 45 ms) |
◻️Google PageSpeed score after applying the plugin
The mobile score rose from 92 to 96 and the desktop score from 99 to 100, while mobile Speed Index went up from 2.6 s to 3.2 s.
![Google PageSpeed score after activating WP Rocket (2025-09-04) [mobile]](https://uknew.co/storage/2025/09/WP-Rocket-%ED%99%9C%EC%84%B1%ED%99%94-%ED%9B%84-%EA%B5%AC%EA%B8%80-%ED%8E%98%EC%9D%B4%EC%A7%80%EC%8A%A4%ED%94%BC%EB%93%9C-%EC%A0%90%EC%88%982025-09-04%EB%AA%A8%EB%B0%94%EC%9D%BC-1024x821.png "WP Rocket Speed Test: Before and After Settings, a WordPress Cache Plugin Performance Comparison 4")
![Google PageSpeed score after activating WP Rocket (2025-09-04) [desktop]](https://uknew.co/storage/2025/09/WP-Rocket-%ED%99%9C%EC%84%B1%ED%99%94-%ED%9B%84-%EA%B5%AC%EA%B8%80-%ED%8E%98%EC%9D%B4%EC%A7%80%EC%8A%A4%ED%94%BC%EB%93%9C-%EC%A0%90%EC%88%982025-09-04%EB%8D%B0%EC%8A%A4%ED%81%AC%ED%83%91-1024x827.png "WP Rocket Speed Test: Before and After Settings, a WordPress Cache Plugin Performance Comparison 5")
|
Item |
Mobile |
Desktop |
|---|---|---|
|
Score |
96 |
100 |
|
First Contentful Paint |
1.8 s |
0.4 s |
|
Largest Contentful Paint |
2.3 s |
0.6 s |
|
Total Blocking Time |
0 ms |
0 ms |
|
Cumulative Layout Shift |
0 |
0.004 |
|
Speed Index |
3.2 s |
1.0 s |
2️⃣ Overall Assessment
Because the server already used Varnish Cache, the improvement after applying WP Rocket was small. Scores and FCP/LCP improved, but mobile Speed Index got worse.
💻 Chrome DevTools analysis
After applying WP Rocket, DOMContentLoaded time was cut from an average of 47.6 ms to 43.9 ms.
Standard deviation dropped from ±5.1 ms to ±2.4 ms, so the measurements varied less.
📈 Google PageSpeed score analysis
|
Item |
Plugin disabled |
Plugin applied |
|---|---|---|
|
Mobile score |
92 |
96 |
|
Desktop score |
99 |
100 |
|
Mobile FCP |
2.6 s |
1.8 s |
|
Mobile LCP |
2.8 s |
2.3 s |
|
Mobile CLS |
0.031 |
0 |
|
Mobile Speed Index |
2.6 s |
3.2 s |
You can see the various advantages of WP Rocket on the official website.
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