Enable - VM Hot memory addBy default you will not be able to add Memory ( RAM) to a running virtual machine. With vSphere4.0 you can add the memory while virtual machine is running using the following power shell script.
Verifying the setting changes in vSphere client after the execution of above script
These settings will not work until the virtual machine is shutdown and started again . Please note that the restart will not enable this setting.
After the starting the virtual machine you will see the following configuration
Following operating systems support the Hot Memory .