I recently moved my development from XP to Windows 7 and found that webpages I had developed were taking 5 seconds long to load. This was unacceptable of course so I had to track down the problem. I eventually tracked down the offending function/method pdo::construct.

I also found that mysql_connect was taking about 1 second to make a connection. After a little googling I found an explaination that php had issues with IPv6 and that you could fix the problem by either disabling IPv6 or switching to the ipaddress 127.0.0.1 when making your connection.