igfxpers.exe belongs to software Intel® Common User Interface and is sometimes used by nVidia graphic cards drivers. It is responsible for enabling display resolution settings to persist when a monitor is disconnected or turned off. Although it might not be essential for desktop computers, many notebook devices might require this process to run on startup. This process can easily be stopped from running on startup from the msconfig and is not essential to Windows 7 or higher operating systems. This file can be usually found in %windir%\system32
On UMPCs this process is essential if you run the display in a scaled resolution, i.e. any other resolution than the native screen resolution (which is 800x480 for all the 2006 era UMPCs with 7-inch touch screen displays). When you shut down/standby/hibernate the UMPC, this process will return the display resolution to 800x480 so that when it restarts the display will be synchronized with the touch screen resolution. If you disable this process, then the screen will not be dropped to the native resolution and when you restart, your touch screen and display will be scaled differently.