How can i improve my site speed...Or i should use another method for changing .php extension.
Check this url.It contains only the following code. <html><body>haiiii</body></html>
The only thing that is slow for me is your external counter and other JavaScript that is loading new data (for whichever purpose I don't know).
Waiting for trafficrevenue.net....
Get rid of all that crap, and there will be no problems. Loading the document itself takes about 200 ms for me, which is normal and fine.
This is a poorly asked question, but nonetheless I think the answer is using the AddHandler feature of Apache. There's no reason you have to send just .php files to the PHP interpreter.
Typically folks will add things like .phtml of .tpl etc. You can add w/e extension you want though.