Hello Yang,
Are you having problems with your 525, i.e. slow connectivity etc ? or are you asking for general information on Pix 525, if you want just general information then there's lot of information on http://www.cisco.com or try http://www.google.com
If you are having problems with packet delay then try cmd 'show interface' and see what type of chip set the PIX has as there is a Cisco advisory on this matter, the folowing link will be useful reading:
http://www.cisco.com/warp/public/770/fn15028.shtml
Hope this helps --
