Theme Speed Tests: Astra Kadence Genesis GeneratePress - Deep Case Study

See how the most popular WordPress themes stacked up in a head-to-head speed test.

Themes Tested

The 4 most popular WordPress themes tested were:

Genesis
Astra
Kadence
GeneratePress

Each theme was tested out of the box.

Then each theme was tested with the same real-world styling, including a home page replete with category images, as well as recent blog posts.

Plus a real-world blog post was tested.

Huge Thank You!

These tests could not have been accomplished without the help of a few of my webmaster designers, who each took on one theme to style.

I want to send a super special thank you to Michelle Phillips of Codefetti for creating the demo site that everyone used, and for her invaluable support to all of the webmasters.

Webmasters and the themes they created for these tests:

Michelle Phillips of Codefetti – Astra
Marcy Diaz of Amethyst Website Design – Genesis
Paula Gregorowicz of The Paula G Company – Kadence
Victoria Gazely (temp home on Facebook) – GeneratePress

I also want to make mention that most of these designers work on a variety of themes, not just the one they are listed with here.

Caching/Optimization Plugin

Thank you so much to Emre Vona of WP Fastest Cache for donating the premium plugin for the ultimate speed tests on these sites.

See this tutorial for my recommended WP Fastest Cache settings.

Who’s the Winner?

You are!!!!

I’m going to be super honest with you.

All 4 of these themes are fast. In fact, they are so close that we are splitting hairs to determine a winner.

And all are great for creating a fast WP site.

Speed is NOT the biggest factor to determine which theme is best for you to use.

Overall GeneratePress was the fastest. That’s because it is nearly a bare bones framework without a lot of styling options. So, if you’re looking for a super minimalistic theme where you can make some easy changes yourself, GP may be the one for you.

Astra and Kadence were pretty even throughout the tests. And they both offer more styling options, especially with their Pro versions, which were not tested here.

Genesis was the slowest, but not by nearly as much in reality as the graphs make it look. BlogAid is on Genesis and it runs like greased lightning. Genesis is also super, duper stable and is a fantastic choice for those who already know they want to hire a designer. Where you can go wrong with Genesis is in the child theme. Some are super bloated and slow. So make sure you get a designer who knows all about speed, like my webmaster designers do.

The Demo Site

Following are screenshots of the Home page and Post used for these tests.

Each theme had a demo site created to look/function the same, to keep these tests as “apples to apples” as possible.

The one shown below is on Astra. And it was designed by Michelle Phillips.

Home Page

Blog Post

Testing Conditions

Following are the conditions I used for server, WP, and more. They matter, especially for folks who want to try to recreate the tests.

Server – LiteSpeed
WP – 5.7.2
No caching at the host
No Cloudflare
Caching/optimization plugin only used on one test
Each page/post tested was displayed in a browser first to warm up caches on the tests where WPFC was used.

The Testers

I ran a LOT more tests, on several other testers, than are shown in this case study summary.

The entire case study – which is about 800 pages – is available to my Webmaster Training members.

Below are the most popular online testers that were used in this case study report, including the testing condition/setup.

GTMetrix Mobile – set to iPhone on a speedy wi-fi connection – which is real-world for most of my client’s users. Tested from the San Antonio location. I have the paid version of GTMetrix which allows these settings. On the free version it will only be desktop from Vancouver Canada.

WebPage Test – set to Chrome on a Cable connection and used for desktop testing. This allows me to see the most requests loaded. Tested from the Utah location.

Google PageSpeed Insights – the default is a Moto phone on a Fast 3G connection, which is the global baseline Google uses. However, this setup is 4x slower than an iPhone, which is the predominant device in the US. It’s also 2x slower than Android. Plus, the score is not about speed. It’s about all of the metrics GPSI includes, plus Google’s opinion on some things, like next-gen format for images. GPSI is, by far, the least helpful tester for actually finding and fixing speed issues. And Google makes zero use of this tester data either. They use their own CrUX report, which provides feedback from real Chrome users – and guess what device they mostly use – iPhones with fast wi-fi. Also, we have no idea about the tester’s location, and it can’t be changed.

All of these testers are now based on the Lighthouse tester – which has 100s of metrics that it checks.

Each of these testers makes use of just a few of those tests that it deems are most important.

All testers include Core Web Vitals.

READ: Core Web Vitals: What You Need to Know and Do for more details on these metrics.

Test Results

Following are the results of all the posts tests run.

The Baseline was on the theme out of the box, and on the Hello World post.

The Salads post was on the demo theme, and mimicked a real-world post.

The Home page was also on the demo theme.

Result Links

Baseline Hello World Post on new theme
- GTMetrix Mobile
- WebPage Test
- Google PageSpeed Insights
Salads Post on Demo Theme
- GTMetrix Mobile
- WebPage Test
- Google PageSpeed Insights
Salads Post with WP Fastest Cache on Demo Theme
- GTMetrix Mobile
- WebPage Test
- Google PageSpeed Insights
Home Page Demo Theme
- GTMetrix Mobile
- WebPage Test
- Google PageSpeed Insights
Conclusions

Baseline Tests

See how each theme tested out of the box with the default Hello World post.

FYI an explanation of each test result is given in this section. Additional sections only have the result graphs.

GTMetrix Baseline

This is the overall grade of the Performance and Structure elements tested, plus 3 Core Web Vitals.

IMPORTANT

For the GTM speed data, the TTFB (Time to First Byte) was subtracted from the rest of the load times.

This is the only test where that was done, and it was to literally remove the initial connection speed from the results, as there is no accounting for all the different mobile connection speeds that visitors use.

This was the best way I knew to evaluate only the theme’s load time.

Grade

The higher the grade, the better.

Genesis = A
Astra = A
Kadence = B
GeneratePress = A

Performance and Structure

Performance Score includes the Lighthouse performance score as captured by this tester. It replaces the PageSpeed/YSlow scores.

It tests:

Loading performance
Interactivity
Visual Stability

Structure Score is GTMetrix’ own assessment of the site’s optimization.

It tests:

Keep-Alive
Combine images using CSS sprites
Use of CDN
Avoidance of CSS imports

Speed

All speeds are in seconds.

The lower the score, the better.

LCP – Largest Contentful Paint – keep in mind there are no images on the Hello World Post, and no logo on this “out of the box” baseline test. So the LCP is the first text on the post, which is the Title. Also keep in mind that this is one of the “adjusted” metrics shown in the Grade section and may not match the LCP shown in the timeline of the other metrics.

TBT – Total Blocking Time – it was 0 on all themes.

CLS – Cumulative Layout Shift – it was 0 on all themes.

TTFB – Time to First Byte – the time it took from the initial host connection until data started being delivered. This time was subtracted from all other load times below.

FCP – First Contentful Paint – when the first thing gets painted on the screen, not matter whether it is an image or text. In this case, it will be text.

LCP – Largest Contentful Paint – this is the “unadjusted” metric, meaning the raw data.

TTI – Time to Interactive – how long a viewer has to wait between seeing something and when they can click or scroll.

Onload – When the post/page reaches the bottom of the devices viewport – meaning all you can see prior to scrolling.

Fully Loaded – when the page/post finishes loading completely, including anything off-screen.

Page Size

In Bytes.

The smaller, the better.

Requests

How many elements have to be loaded to display the post/page.

The lower, the better.

WebPage Test Baseline

Following are the WPT results for the Hello World post.

This test is for desktop load, which will have more requests.

Speed

These results are pretty indicative of the overall test results under all conditions.

From fastest to slowest, the themes ranked:

GeneratePress
Astra
Kadence
Genesis

Requests

As you can see, Genesis is by far the heaviest on requests at 20, but Kadence is not far behind at 17.

Astra is the lightest at 9, but closely matched at 10 for GeneratePress.

Bytes

It’s not all about how many requests there are. It’s about how much they weigh.

And the themes followed the speed results with GeneratePress first and Genesis last.

Google PageSpeed Insights Baseline

Score

This is not a speed score!!!

This is the overall score for all elements tested, plus Google’s opinion on a few of them.

Speed

The overall speed, mostly Core Web Vitals, but the real weight is put on TBT and TTI. Even if your site loads fast, if folks have to wait to scroll or interact with it, they leave.

Square

Below the Lab Data are a series of frames. There is no timeline attached to them, but it does give some visual indication of what the tester sees as the page/post loads.

This graph shows what “square” the post loaded in where it could be read. Note that some themes fade in the page. This is the square beyond that fade in.

Eliminate Render Blocking, Reduce CSS and JS

GPSI has several metrics below the Lab data with Opportunities and Diagnostics.

This graph shows themes that had issues with the elements that most commonly cause speed drags.

Chains and Request Count

The load order of each theme is different, as are how many elements are loaded. Both can cause speed drags.

The lower the number on each, the better.

Audits Passed

The total number of audits, at the time of this testing, is 38.

This graph shows how many were passed by each theme.

Salads Post

See how each theme did with a real-world post with the demo theme in play.