A recent post on the official Joomla! community forum claims that Joomla! 1.5 uses more resources than Joomla! 1.0. Considering the new design and architecture of the Joomla! 1.5 code, the conclusions of the test are quite surprising.

A user installed Joomla! 1.0.13 and Joomla! 1.5 on a local server running PHP 5.2. The user then proceeded by measuring the memory usage, load times, the number of files loaded and the number of SQL queries executed.

What are the results? The administrator control panel in Joomla! 1.0 loads in 0.0165 seconds, uses 2.9Mb of memory and loads 37 files. In Joomla! 1.5 the control panel loads in 0.107 seconds, uses 4.5Mb of memory and loads 89 files. The front-end showed similar results. The Joomla! 1.0 homepage loads in 0.087 seconds, uses 3.8Mb of memory and 44 files but in Joomla! 1.5 it takes 0.228 seconds to load, uses 6.1Mb of memory and 153 files. After similar tests it is found that Joomla! 1.5 takes more than three times as long to execute.

What's interesting is that the test was done on PHP 5, which many say is much faster than PHP 4. Joomla! caching was disabled as well during the testing.

Is this a major concern? It could be, depending on who's hosting your web site. If you are using a shared host with an overloaded and underpowered server than upgrading your web site to Joomla 1.5 may not be the best choice.

The original post Our Experience with J1.5 Load Times & Memory Usage is available on the Joomla! community forum. Since Joomla 1.5 Stable has been released, it would be nice to see official tests and benchmarks done by the Joomla! core team.