Troubleshooting Nginx

Hey guys,

So I recently switched to Nginx with the help of guys at Dreamhost to reduce the load on my private server. Things were fine and dandy until I started getting timeout Gateway errors 2 days after. The guys at Dreamhost created a cron job to restart the server everytime it went down (it was not coming back up by itself ). And now I am consuming as much as I was with Apache again. Anyone knows how to optimize Nginx to reduce the load? I tried using APC but Dreamhost told me it won’t work on their private server. The problem seems to be too many PHP children but I am not sure how to fix that.