[syslog-ng]syslog-ng performance

Hi All, I'm currently using syslog-ng on 8 of mta/mailhost machines which are logging via tcp to a central loghost/server.. Each machine generates over 1 gig of logs.. syslog-ng is eating away at system resouces in a big way, up to 40% of the cpu (local logging is disabled).. Is there any optimizations that can be made to try and chop down on cpu usage? Perhaps a higher sync() value? Its currently set to 0.. Regards, Cami