localhost vs. 127.0.0.1 in mysql_connect()

Question

1. Does using localhost in mysql_connect() make the connection faster than using 127.0.0.1?
2. What is the connection type between the PHP script and mySQL (when using the mysql_connect() function) ? Is it TCP/IP?

Answer 1

1. Differs between Windows and Linux. If you use a unix domain socket it'll be slightly faster than using TCP/IP (because of the less overhead you have).
2. Windows is using TCP/IP as a default, whereas Linux tries to use a Unix Domain Socket if you choose localhost and TCP/IP if you take 127.0.0.1.