Prime purpose of this lecture is to presentation on Central Processing Unit (CPU). The Central Processing Unit (CPU) is the single most important component in a computer system. The CPU coordinates almost all activities in a laptop or computer system. The CPU is sometimes termed as the computers “brain”. The actual major concepts of CPU’s tend to be: Speed of CPU’s, CPU Components, How CPU’s work, Manufacturers of CPU’s, CPU sockets and Cooling of CPU’s. Here briefly explain all of this major concepts of CPU. Finally discuss on MMX Technology.