I run mostly vbulletin. And these .so are loaded extension = "pdo.so" extension = "pdo_sqlite.so" extension = "sqlite.so" extension = "pdo_mysql.so" extension="apc.so" extension="timezonedb.so" extension = "memcache.so" I use APC. I am not sure about timezonedb.so, what is it? About memcache.so, i plan to remove it. About the rest (pdo, pdo_sqlite, sqlite), i am not sure what is it. pdo_mysql.so, i think it is for normal mysql code, so i need it. Thank you.