Zend Compiler / Cache

it is said that the Zend Cache would store in the Web server's memory an intermediate coded version of a PHP application. and the Zend Compiler saves the code in a closed Zend Intermediate Code format Does anyone know if the "intermediate code" formats for each product are different? It would be nice (and also expected) that the intermediate code at the Zend Compiler would speed up execution time as the Zend cache will do. But there's not much technical info about it at the zend homepage. Any clues? Thanks Alex