asterisk13 conference's question

astersisk version: 13.0.0 and 13.3.2
question: The module app_meetme.so was loaded for conference. When users(SIP or DAHDI) enter conference, device’s CPU rises high, it’s not appear in asterisk-1.6. I compared function conf_exec in app_meetme.c with asterisk-1.6,not big difference. Need Help