httpd.conf

StartServers 2 
MinSpareServers 2 
MaxSpareServers 6 
MaxClients 10 
MaxRequestsPerChild 300    

apc.ini

extension = apc.so
apc.enabled = 1
apc.shm_size = 64M ;; depends on how much RAM is available
apc.user_ttl = 7200
apc.ttl = 7200 ;; I've read that a zero value is recommended sometimes
apc.stat = 0 ;; 1 on development server
apc.slam_defense = 0
apc.mmap_file_mask = /tmp/apc.XXXXXX