OK; so for serving multiple concurrent clients ISAPI would sound to me
like the better choice, since it can use threads, or what would be the
advantage of using fastcgi?
Non-threaded PHP is faster than threaded PHP, because it doesn't need to do locks between threads and keep the thread context through the code, etc. So FastCGI usually would be faster and also more stable since the memory space is not shared. It forgoes some advantages of threaded application, but overall it is faster.
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Stanislav Malyshev, Zend Products Engineer
stas@zend.com http://www.zend.com/