ah, voila, j'ai retrouvé celui que je cherchais : turk mmcache :
http://turck-mmcache.sourceforge.net/index_old.html

Turck MMCache is a free open source PHP accelerator, optimizer, encoder and dynamic content cache for PHP. It increases performance of PHP scripts by caching them in compiled state, so that the overhead of compiling is almost completely eliminated. Also it uses some optimizations to speed up execution of PHP scripts.

Turck MMCache stores compiled PHP scripts in shared memory and execute code directly from it.

sur la page, il y a un bench des différents caches d'opcode php, d'ailleurs ^^

et http://developpeur.journaldunet.com/tutoriel/php/040209php_systemes_cache1a.shtml y'a quelques mots sur les caches d'opcode, à priori (juste survolé le début, pas tout lu )