In any VPS with cPanel or unmanaged VPS you are limited to the amount of cpu, memory, space and bandwidth you can use. Those limits can be checked on our web site at https://www.scalahosting.com/vps.html.
With your VPS you have guaranteed memory and burstable memory. The guaranteed memory is the memory assigned to your VPS which is available at all times. When the VPS runs out of guaranteed memory it can use from the burst memory if only it is available on the server. Burst memory is memory which is currently free on the server and not needed by any of the other VPS’s on the server. If your VPS starts using from the burstable memory you should consider upgrading to a higher VPS plan because if your VPS is using burst memory and at the same time another VPS needs more memory which happens to be within the guaranteed memory limit for it then the processes using the burst memory on your VPS will be killed to free up memory for the other VPS. This is why the best practice is to upgrade to a higher plan when starting to use burst memory. That avoids crashing of your applications and allows your VPS to operate normally.