Without doing an analysis, which is really warranted, here are some coarse grain recommendations: 1) Get off VPS if you can. If you can't check out linode.com;

Without doing an analysis, which is really warranted, here are some coarse grain recommendations: 1) Get off VPS if you can. If you can't check out linode.com; they offer better price/performance than most cloud services. 2) Take a look at the Percona build of MySQL - it is faster, especially with more cores. 3) Use in memory tables if possible 4) Switch to InnoDB or XtraDB (in the case of Percona) tables... MyISAM implements table level locking, whereas InnoDB and XtraDB implement only row level locking.