Continuing in his series of benchmarking various statistics about PHP, Sebastian Bergmann has created a few more interesting bits of information. This time, gives the results of running bench.php on the numbers he ended up with (and made some spiffy graphs out of them as well).
According to his numbers, a real speed boost was made in compile time when PHP 5.1.6 came on the scene. PHP 5.2 changed things very slightly, slowing things down just a bit (on both the GCC 3.4.6 and 4.1.1). The ICC compiles saw a similar jump in speed with 5.1.6.
So which is faster overall? Well, as the last graph shows, even starting from PHP 4.4.4, the ICC with the "fast" option beats either version of the GCC compiler by a good margin.
Oh, and if you'd like to run some stats yourself, he includes the raw data he found when making the compiles.