Magento performance + hosting optimalisation

Dear Freelancers, We are running a multiple magento website with 33 store views on a dedicated server with Directadmin. We have some heavy performance troubles, en the server get a lot of times overloaded. There where a several server admins who checked already and no one can find a solution to get the magento shop stable. Also we got troubles with saving products in magento after a while the server get slow and overloaded. Before you can start i can give you acces to new relic so you can monitor the processes. We need a real expert who can help us to fix this only bid if you are a real magento hosting pro. See attachment for the running processes when the server is overloaded. For the server specs see attachment. Regards Dominique