Testbed and methods
For testing the impact of the various caching modes, I installed an Apache + Joomla instance on a Dell D620 laptop machine. The details are the following:
- Core2 T7200 CPU @ 2.0 GHz (dual core, 4 MB L2 cache)
- 4 GB DDR2-667 RAM
- Quadro NVS110 videocard (used in text-only mode)
- Seagate ST980825AS 7200 RPM 80 GB SATA hard disk drive (in IDE compatibility mode, as the D620's BIOS does not support AHCI operation)
- O.S. Debian Testing (codename “wheezy”) amd64
Joomla and PHP performance where measured by using a second laptop running Apache Benchmark, configured to issue 500 requests with a concurrency level of 4. In order to obtain reproducible and accurate results, powersaving was disabled. This means that the CPU always run at it maximum frequency (2.0 GHz in this case).