I've seen that using eAccelerator as PHP caching system (cache 16 MB), "yii.php" is faster than "yiilite.php". Is this normal?
ab -n 1000 -c 25 http://localhost/yii/demos/helloworld/
About 295 #/s using yii.php and 220 #/s using yiilite.php
I've also compared these results to KohanaPHP (another framework), it is about 245 #/s using eAccelerator while it is slightly faster than Yii without eAccelerator (similar to your CodeIgniter results with/without APC… in fact Kohana is a fork of CodeIgniter… but there CodeIgniter + APC is faster than Yii.php + APC and slower than Yiilite.php + APC, while here the faster one is Yii.php).
I just tried eAccelerator with the same set up as described on the performance page. I got these numbers:
Yii using yii.php: 337
Yii using yiilite.php: 387
CI: 393
When you do the test, make sure you "stop" and "start" apache each time you begin to test a new setup. Also, you should open your browser to access the URL for a couple of times before testing. This will ensure the test is done properly without interfering each other.
What is the version of Yii that you are testing with?
It is interesting to see that yiilite.php is slower than yii.php in your tests when server caching is enabled. While on my windows box and linux box I saw yiilite.php is much faster than yii.php, I do observer some independent tests gave opposite results.
Anyway, the upcoming 1.0.1 version has been optimized further more to make yii.php even faster.
