Wampserver/Codeignitor Mysteriously Runs SLOW when running PHP 5.2.9-2 instead of 5.3???

[eluser]Unknown[/eluser]
A few minutes ago I could not figure out why my code ignitor/wampserver 2.0 computer was serving pages sooo SLOW. I remembered that I had switched from 5.3 to 5.2.9-2 about an hour earlier. So, after switching back to 5.3, my pages were magically fast again. I thought I would share this most strange phenomenon. Any speculation as to why this might have happened?