I spend the most interesting past two weeks downloading all 430 WordPress themes that were updated less than 365 days ago.

I then measured their page load times using Firefox Firebug as well as YSlow and Page Speed.

Then I summarized the results. Very interesting stuff.

I also graphed MySql number of queries, Yslow and Page Speed scores, Dynatrace time to first impressions, etc …

Many graphical results are enjoyable here in several interactively searchable and sortable tables.

Screenshots of the fastest loading WordPress themes are here

Interesting graphs summarizing several aspects of WordPress theme load times.

So even though I spend two weeks doing the tests and another week learning the graphing programming and drawing the graphs, this is first official post about it. I do not comment about the graphs or results; these graphs are all available for use on your websites: to write your own articles and give your own opinions and interpretations to your website visitors.

Interesting; but how to act based on this information? I would like to read your articles and adjust my forthcoming tests based on the comments in your articles.

These page load time measurements were done on my local computer, with a local Apache server running on CentOS 5 install within VirtualBox within ( yes ) Windows 7.

Please note that all you website visitors WILL have significantly worse times than those you find published on my webpages.

Since your website visitors are not browsing your website with their computer directly connected to your website host … in the same room … there will be network latencies (delays).

I did all the tests using my currently very new WordPress website with only 3 posts and one page.

For ALL future tests I will be using a test WordPress installation using the 1000 demo posts and pages I already generated. That test WordPress also contains 5000 comments.

So there will be WordPress themes that I tested that will do worse, since their database accesses is slow. I did not test that with this first test.

I already compared the Firefox 4 page load times against Firefox 3.6 ( that I used for all tests ).

Unfortunately even though Firefox 4 is faster than 3.6, I found very little difference in page load times. A quick investigation revealed that other things make a page slow; things Firefox 4 cannot help with; like 25 images on a page.

Since most of your website visitors will be using 3.6, not the 4.0 beta; I will continue to do all my tests using 3.6 … the current standard.

I am currently busy doing a similar, but also different, set of tests comparing how these page load times differ when using the following:

Total Cache
Super Cache
Hand tuning – no Caches
NgInx
Lighttpd
Litespeed
Apache
Each time I test the full set of 400 WP themes it takes 2.4 hours.

So I cannot run all the above (plus their interesting combinations) 4 or 5 times to get good averages. I will therefore use only the top 30 themes vs the worst 30 themes ( eliminating the worst 10 themes that should not even be on wp.org ).

Please do not quote me out of context on the text below:

Conclusions I am investigating – results TO BE DETERMINED below:

Super Cache makes the top themes load 2 times faster.

Using ALL Total Cache features makes the top themes load 20 times faster.

Hand tuning takes 40 minutes with results nearly 75 percent as good as Super cache.

Apache is the reference CPU load and RAM implementation.

Lighttpd uses 50% less cpu to serve the top themes 2 times faster.

Lighttpd uses 75% less cpu to serve the worst themes 5 times faster.

Nginx uses 50% less cpu to serve the top themes 2 times faster.

Nginx uses 75% less cpu to serve the worst themes 5 times faster.

Obviously there will be graphs.

Your comments invited below.

Thanks

Originally posted 2013-04-04 11:17:08.