An Auto Deployed ESXi server will always have to perform PXE boot, engage the Auto Deploy server or the vCenter database (if it has the information of the image profile and the host profile). This is because the ESXi image is not stored on the machine but is loaded directly into the server's volatile memory. So, every reboot requires the server to go through the PXE boot procedure to load an ESXi image into its memory. Starting with vSphere 5.1, you can use Auto Deploy to install the ESXi image onto the local disk of the chosen server. This process is referred to as a stateful install.
The following procedure will help you prepare a host for a stateful install:
Extract a host profile from a reference host and edit the settings.
Expand Advanced Configuration Settings and then check the System Image Cache Configuration checkbox.
On the right pane, use the System Image Cache Profile Settings drop-down menu to select Enable stateful installs...