server ram + cpu overload issue

Hi All,

need your quick and smart adviser here
system information :
1.Azure cloud
2.machine Spec - 1 core 2.4 / Ram 3.5 GB / Disk plenty of space  
3.OS Spec - Ubuntu server 14.04 up to date
4.panel - sentora latest
5.users hosted - 5

my monitor is show me that cpu and ram is around 80% most of the time
any guiding for solving this will be appreciated,
i think that the current configuration should not be user more then 1.5gb of ram also cpu should be idle most of the time.  

thank you.