es4mxlum.dll is a GSUMPD
belonging to User Mode Printer Driver for Windows 2000//XP
from Agfa Monotype Corp.
Non-system processes like es4mxlum.dll 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.