Some of the first benchmarks of Drupal 5 vs. Drupal 4.7 are now surfacing, and for you OSS fans out there considering an upgrade, the news is good. For the laggards amongst us, you all have one more reason to get off the couch. So the lead of the Drupal Project, Dries Buytaert decided to put the newer Open Source CMS up against the older and still much more popular version. Perhaps Buytaert is just trying to move people long, but regardless, the numbers are interesting an positive.
His recent blogpost is not long winded and the gist is that Drupal 4 and 5 behave about the same until you enable one of the several v5.0 caching modes.
When normal caching is enabled, Drupal 5 users will see a pretty significant increase in speed -- 75% over Drupal 4.7 with caching, especially under a heavy load, and across the board. If you move to aggressive caching, which could bypass and play havoc with some modules (so RTFM), your speed increase almost triples. This is illustrated in the graph below. Drupal 5 Performance To test, they set up a pretty large Drupal 4.7 site with 2,000 users, 5,000 nodes, 5,000 path aliases, 10,000 comments and 250 vocabulary terms spread over 15 vocabularies. The main page was configured to show 10 nodes, enabled some blocks in both the left and the right sidebar, setup some primary links, and added a search function at the top of the page. Then, an exact copy of the Drupal 4.7 site was made and upgrade to the latest Drupal 5 release. The result is two identical websites; one using Drupal 4.7 and one using Drupal 5.
Benchmarks were conducted on a 3 year old Pentium IV 3GHz with 2 GB of RAM running Gentoo Linux. They used a single tier web architecture with the following software: Apache 2.0.58, PHP 5.1.6 with APC, and MySQL 5.0.26. No special configuration or tweaking was done other than what was strictly necessary to get things up and running.
Additional efficiencies introduced in Drupal 5 including CSS preprocessor and mod_expires caching which have a significant impact on the page loading were not included in this test but will probably make significant positive impact on page speed.
Overall the performance gains are notable and for us, compelling. The Drupal 5 release was really more focused on platform and administration usability. So its an added bonus that in addition to simplified interfaces, your server load should also be dropping.
One thing to bear in mind is that much of Drupal's caching capabilities are only enabled for anonymous users. Once someone logs in, the amount of dynamic, personalized content tends to nullify the ability to cache pages and components. This limitation is true for both the Drupal v4 and Drupal v5 series of releases.