We're using MediaWiki on our corporate Intranet with great results. It's perfect even for a smaller company.
The configuration is as follows: MediaWiki (http://wikipedia.sf.net/): 1.4.4 PHP (http://www.php.net/): 4.3.10 (apache2handler) MySQL (http://www.mysql.com/): 4.0.18-max-debug-log IIS 5.x Windows 2000 Server on 2Ghz Pentium 4, 512MB RAM, SCSI RAID array Also: Apache 2.0.52 for testing
This rather non-trivial server gets a 100% CPU spike for 2 to 5 seconds on each page view in the wiki. Ugh!
Apache on that same server didn't give any noticable speed improvements.
Just on a whim, I installed the same MediaWiki code on a Linux laptop, running PHP 4.3.10 and the same Apache version. It's querying the MySQL database on the main server.
The Linux/PHP/Apache on the Pentium 3 850Mhz laptop with half the RAM is nearly FOUR times faster! That's half the RAM, a third the CPU speed... but it dusts Windows 2000.
I can bring up two browser windows, with the Windows wiki in one and the Linux wiki in the other, and click "Random page" in both windows. I can click thru 4 or 5 random pages in the Linux instance in the time the Windows instance brings back one.
To get Windows performance like that, I had to run the PHP code on a dual CPU P4 with 1GB RAM under Windows 2003 Server.
Are there any optimization options I could be missing? I've already enabled page caching on the server (works well), installed the Zend Optimizer (free version), and ensured that I'm not dealing with the dreaded multi-redirect bug. The CPU hit on the Windows server is huge. MySQL isn't breaking a sweat at all.