Allright, here is the newest technology
They say that PHP has been running 120% faster than on Unix system..
http://www.microsoft.com/uk/servers/winclientshearts/
To be honest, I am a fan of Windows, but the desktop OSes..
The servers are not so good beacause, they were written in a bad way.
But the famous organization Zend (that created the modern PHP engine) is guaranteeng that it will work:
http://devzone.zend.com/article/3233-Windows-Server-2008-Now-PHP-Ready
Me, personally, I would never belive that something written for Unix, will work better in Win32 enviroment..
I am now testing this solution to see if it is better, so give me scripts to try!