Is lighttpd faster than Apache? Can Wordpress handle high traffic websites? Rumors spread like wildfire on the web, and sometimes it’s hard to separate the truth from evangelism and clever marketing. Today I’m going to put Wordpress to the test, running under Apache and lighttpd, and see if a clear winner emerges.

To find out more about how I came up with these numbers, check out my post explaining how to measure your web site’s performance.

For these tests I used ab, a popular benchmarking tool distributed as part of the Apache project. I ran each test multiple times, varying the number of concurrent connections. The results below show the maximum number of requests per second each server could handle with a default installation, with APC installed, and with WP-Cache enabled.

lighttpd_vs_apache.jpg

The results are pretty clear: lighttpd won by a longshot. I use Apache, and was actually pretty impressed with these results. It’s not that lighttpd won (that much I expected), but that the margin was so large (roughly 50% for the second two tests). It’s also fairly clear that Wordpress, properly configured, can handle a huge volume of traffic. Even six requests per second is quick enough for most blogs. Keep in mind, however, that this test was run on a fairly powerful dedicated box (Sun Ultra 20; 1.8GHz AMD64 Processor; 2.5GB RAM). If you’re using a shared hosting provider, and need to handle a lot of traffic, install WP-Cache.

One question remains: is the performance gain worth the switch? This you’ll have to answer for yourself. For me it’s not. The performance I get from Apache is sufficient, and the support and community more than compensate for deficiencies elsewhere. If performance became an issue, however, I wouldn’t hesitate to make the switch.