Which is faster, SSI or PHP?

I am going to redesign my site, currently it uses SSI (for the menu and stuff). I know php can do a ton more stuff then SSI, I actually use php for certain pages as needed throughout the site. But was wondering if php would run faster for what will basically be SSI commands (namely just what would be the php equivlent of ReadFile()). For something like that, would php be faster or would the speeds generally still remain the same? Again most of the requirements I need can be handled by SSI, not going to use MySQL or anything of that nature for the major chunk of the site. Another concern I have is searchability by search engines. For example, if I move everything to php and just use a different text file for each page for the main body of text and load each text file depending on what page the user wants, would the search engine search though those text files and just link to those and not to the php file? Would it even be spidered by the search enging properly? -- Todd Eddy vrillusions@mail.com www.vrillusions.com