WP Speed of Light Review: A Quality WordPress Performance Plugin

If you’re running a WordPress website, you should always be on the lookout for ways to speed up your site.

As I harp on in every post that I write, page speed has far-reaching effects on your site. I’m talking about important issues like user experience, conversion rates, and organic Google rankings.

But page speed optimization can be hard to grasp, especially if you’re not a power WordPress user.

To help fix that, WP Speed of Light is a freemium WordPress plugin that aims to make it simpler and easier to speed up your WordPress site. Essentially, it aims to be an all-in-one solution for WordPress performance.

In my WP Speed of Light review, I’ll share just exactly what goes into making WP Speed of Light an all-in-one solution. Then, I’ll put it through a test on a live website and see how much it can improve page load times.

WP Speed of Light Review: A Look At The Performance Features

WP Speed of Light is a free core plugin (listed at WordPress.org) that also offers a premium add-on with even more performance optimizations.

I’ll install both the free plugin and premium add-on for my tests, but I’ll break the feature list into two sections so that you know exactly what you get with each version of the plugin.

The free version of the plugin handles:

  • Page caching
  • Selective or global cache by device
  • File grouping
  • GZIP compression
  • Remove query strings (an annoying warning on most people’s Google Page Speed Insights score)
  • Browser cache (another common Google Page Speed problem)
  • Minification – HTML, CSS, and JavaScript
  • Database optimization – post revisions, spam comments, transients, etc.
  • CDN integration
  • In-dashboard performance reports, both for page load times and database queries

And if you upgrade to the Pro version, you’ll also get:

  • Image compression – either 1 GB or 3 GB of usage
  • Google Fonts optimization (group all fonts as a single file)
  • Cache preloading – ensures that the first visitor to your page after a cache cleanup doesn’t have to wait for the cache to generate
  • Visual file exclusion for minification and grouping (helpful if one of those two features is causing an issue with a file)
  • DNS preloading – reduces the time it takes for DNS resolutions from external domains
  • Automatic database cleanup – schedule the cleanup rather than doing it manually like the free version offers.
  • More advanced cache exclusion rules, including wildcard and user role exclusions

I know I just threw a lot of features at you. So let’s dispense with the theoretical, jump into the plugin’s interface, and then run some tests.

How To Set Up WP Speed of Light

Once you install and activate the plugin(s), WP Speed of Light gives you this nice dashboard with an overview of your site’s performance:

wp speed of light review - the dsahboard

Beyond the dashboard, you also get 6 different menu areas to further configure/utilize the plugin:

Speed Analysis: Page Speed And Database Query Tests

In the Speed analysis area, you can:

  • Run page load time tests using the WebPageTest API
  • Monitor database queries for specific pages

wp speed of light test

In general, this area is more about helping you monitor your site’s performance than actively improving your site’s performance.

Speed Optimization: Where You Speed Things Up

The Speed optimization area is where you’ll actually make the tweaks to speed up your site.

In the Speed Optimization tab, you can configure the cache settings for your site:

turn on caching

In the Minify & Group Resources tab, you can configure the various minification settings and/or group different resources together:

minification and file grouping

And in the Advanced Optimization tab, you can configure cache preloading and DNS pre-fetching (I left these options off for my testing):

advanced performance settings

Database Cleanup: Optimize Your Database

I skipped the Image Compression tab because it’s a CTA to take advantage of free credits using the separate ImageRecycle plugin.

In the Database cleanup tab, you can optimize your entire database or just deal with specific tables. And you can also create an automatic schedule, if desired:

wordpress database cleanup

CDN integration: Exactly What You’d Expect!

The CDN integration tab helps you connect to an external CDN service. I’m not using a CDN on my test site, so I wasn’t able to personally test this feature. But based on my experience with the rest of the plugin, I’m going to assume it works as described:

Configuration: Other Minor Settings

Finally, the Configuration area helps you configure some other settings like:

  • User roles to exclude from optimization settings
  • WebPageTest API key

And that’s pretty much all there is to it! Overall, WP Speed of Light is pretty simple to use.

WP Speed of Light Performance Test: What The Data Says

Here’s where we find out if that lengthy feature list above actually translates into a noticeably quicker website.

To test that, I’m going to run a little before/after test. I’ve set up a test site on my SiteGround GrowBig plan. Here are some details on my website:

  • Using an Elementor landing page template with Elementor Canvas (this essentially removes my theme from the equation)
  • Is ~1MB and has 57 external requests

Beyond WP Speed of Light, I haven’t done a single thing to improve the performance of the site.

I’ll run two sets of tests:

  • GTmetrix – shows how quickly my site loads for a single visit.
  • Load Impact – shows how quickly my site loads for 25 visitors spread over 5 minutes.

Let’s see how it goes!

Before: Test Site Loaded In ~1.8 Seconds

Ok, here’s how my test site did before installing and configuring WP Speed of Light.

Testing from GTmetrix’s Vancouver, Canada server, my test site loaded in 1.8 seconds:

That’s definitely not horrible for an unoptimized site (SiteGround is pretty good!), but it’s also nothing to phone home about.

To see how my unoptimized site performed under some load, I also ran it through Load Impact:

The blue line represents the number of active users, while the green line represents how long the page took to load. You can see that, with the exception of a spike at the beginning, my test site was actually pretty consistent for every subsequent visitor, with load times hovering around 1.2 seconds.

After: Page Load Times Reduced By 50%+

Ok, if you recall from my first test a second ago. The unoptimized version of my site:

  • Loaded in 1.8 seconds
  • Was a little bit over 1MB
  • Had 57 requests
  • Scored 90% in PageSpeed
  • Scored 78% in YSlow

After optimizing my site with WP Speed of Light, those numbers improved across the board:

  • Load time cut in half to 0.9 seconds
  • Page size cut to 945 KB
  • Requests knocked down to 28
  • PageSpeed Score up to 100%
  • YSlow score up to 89%

Not bad for a couple mouse clicks!

As with my before test, I also put my optimized site through Load Impact. With the exception of a weird spike in the middle (which I don’t think is WP Speed of Light’s fault), my test site’s page load times dropped to 450ms for each virtual user, which is a little over 50% reduction:

How Much Does WP Speed of Light Cost?

First off, you can always use the completely free WP Speed of Light plugin listed at WordPress.org.

If you want the premium features, you have two options:

  • Pro Version + 6 Months of Support & Updates – $34 – gives you 1 GB image compression in addition to limited support/updates
  • Pro Version + 1 Year of Support & Updates – $44 – gives you 3 GB image compression in addition to the extra support/update period

Final Thoughts On WP Speed of Light

To recap, here’s how my test site did before and after using WP Speed of Light:


Load Impact Avg.


1.8 seconds

1.2 seconds


0.9 seconds

0.45 seconds

You do the math!

There are a ton of WordPress optimization plugins, so I don’t have the data to definitively compare WP Speed of Light to other solutions. But I can definitively say that WP Speed of Light will probably speed your website up a good deal.

At least for my test website, I saw page load times decrease by 50%+.

So, if you want to see how it can speed up your site, click below to get WP Speed of Light:

Get WP Speed of Light Free Get WP Speed of Light Pro Add-on

Other interesting posts on WPLift

Colin Newcomer

Colin Newcomer

Colin Newcomer is a freelance writer and long-time Internet marketer. He specializes in digital marketing, WordPress and B2B writing. He lives a life of danger, riding a scooter through the chaos of Hanoi. You can also follow his travel blog.

11 thoughts on “WP Speed of Light Review: A Quality WordPress Performance Plugin

  1. That looks pretty cool. I might have to give this a try, vs my usual W3 Total Cache and see how it does. I like the simple config, which is a big improvement over W3, and a lot easier for more novice users.

    Thanks for the write up!

  2. On their home page they have that based on 17 ratings they got “84 out of 100” on WP.org but the image they used shows 5 stars, I don’t believe WP.org shows 5 stars for “84 out of 100” which comes out to 4.2/5
    They shouldn’t be doing these kind of things…

  3. Hi Colin,

    So I assume on siteground this replaces their default SG Caching plugin? I’m fairly happy with their SG Caching plugin but always looking for any speed improvements. Have you tested with both to see the performance difference?


  4. Thanks Colin for your article. Finding a suitable WordPress plugin always needs some serious brainstorming to get the ultimate optimization. The above-mentioned Plugin just helps me a lot to gain the highest speed for my site. It is really effective and working smoothly.

  5. Hi Colin,
    just made a comparison of several caching plugins and tried the free version of speed of light. Very good results! The site performed much better than with wp fastest cache or hummingbird and the setup was very easy compared to W3 TC.

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