I just posted this to StackOverflow in response to a question about PHP sockets:

Actually it is my experience that PHP5 sockets are quite good. They are written in C and built-in to the PHP5 binary, so they would run quickly, as opposed to being implemented in PHP itself.

Check out nanoweb and nanoserv:

http://nanoweb.si.kz/

http://nanoserv.si.kz/

The author has done an impressive job of putting PHP sockets to work, building a highly capable pure-PHP webserver with nanoweb, and a complete server daemon framework for PHP 5.1+ with nanoserv.

Looking through the nanoserv documentation and code base may give you more confidence in PHP sockets.