sdii.exe is an executable of the Microtek Scanner Console. This process will allows computer to scanner communication e.g. automatic scanning when the 'go' button is pressed.
Non-system processes like sdii.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues