Recently, I figured I’d look into some WordPress caching options. Rather than setting up my own caching service, I figured I would try out some of the available caching plugins. Note: I only looked at the free versions of each plugin.
So, after a quick download of jmeter, and jmeter plugins, I created a basic test plan to load the home page, several articles, and all articles by a single tag (hawaii).
Keep in mind this was an extremely basic benchmark. No resource utilization was captured from the host servers (Apache or MySQL).
The initial results were interesting. Most seem to make no difference, under moderate load, what-so-ever, in terms of the site’s performance. Some made the load times even slower. The following graphs show the results for the same tests, at increasing load over time (threads).
Initial Findings
Looking at 5 concurrent threads loading the Home page as the comparison for each test, there is a slight improvement of about 100 to 300 milliseconds for all the Caching plugins, except W3 Total Cache (Edge Enabled), which is about 200 milliseconds slower than no caching at all.
Looking at the Home Page specifically:
At 5 concurrent threads, here are the average load times:
- No Cache: ~800ms
- Quick Cache: ~500ms
- W3 Total Cache: ~700ms
- W3 Total Cache (Edge Enabled): ~1,000ms
- WP Fastest Cache: ~600ms
 No Cache Plugin: Response Times over Threads |
 WP Fastest Cache: Response Times over Threads |
 W3 Total Cache: Response Times over Threads |
 W3 Total Cache (Edge): Response Times over Threads |
 Quick Cache: Response Times over Threads |
Conclusion
If you are looking for some basic improvement in page load time, your best option is Quick Cache, based on the data. Even though the improvements are minimal, I am currently running Quick Cache, based on my findings.
The argument could be made that given how little these plugins affect the response times, it’s not worth installing any caching plugin at all. I’m not sure I would pay $200 for W3 Total Cache, either. 🙂 Furthermore, don’t make the assumption that adding a caching plugin will magically improve your site’s performance.
