Description:
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According to http://php.net/manual/en/intro.wincache.php:

The Windows Cache Extension includes 5 different types of caches. The following describes the purpose of each cache type and the benefits it provides.

    PHP Opcode Cache - PHP is a script processing engine, which reads an input stream of data that contains text and/or PHP instructions and produces another stream of data, most commonly in the HTML format. This means that on a web server the PHP engine reads, parses, compiles and executes a PHP script each time that it is requested by a Web client. The reading, parsing and compilation operations put additional load on the web server's CPU and file system and thus affect the overall performance of a PHP web application. The PHP bytecode (opcode) cache is used to store the compiled script bytecode in shared memory so that it can be re-used by PHP engine for subsequent executions of the same script.

As explained in https://forums.iis.net/t/1229349.aspx?WinCache+2+0+0+release+on+SourceForge Opcode cache was removed from Wincache a while ago.