Any website on our shared servers that uses a high amount of server resources (CPU, memory usage, and network resources) will be given an option to pay for a dedicated server or VPS. The abuse and misuse of shared system resources is a serious problem. Accounts on a shared server must share resources with other users so we must limit how much of the CPU and memory that can be used by any one account.
In all fairness, we cannot allow one or two clients to use all of the system resources on a shared machine and have all other clients suffer because of it. Excessive CPU & memory usage by one or more clients causes extreme slowness in all areas: MySQL, Email, HTTP and more. If the CPU & memory usage by a few clients gets out of hand, all sites hosted on the machine will return errors and not be accessible in any way.