The Pentium II can execute all the instructions of all the earlier members of the Intel 80x86 processor family. There are four versions targetted at different user markets. The Celeron is the simplest and cheapest. The standard Pentium II is aimed at mainstream home and business users. The Pentium II Xeon is intended for higher performance business servers. There is also a mobile version of the Pentium II for use in portable computers.
All versions of the Pentium II are packaged on a special daughterboard that plugs into a card-edge processor slot on the motherboard. The daughterboard is enclosed within a rectangular black box called a Single Edge Contact (SEC) cartridge. The budget Celeron may be sold as a card only without the box. Consumer line Pentium II's require a 242-pin slot called Slot 1. The Xeon uses a 330-pin slot called Slot 2. Intel refers to Slot 1 and Slot 2 as SEC-242 and SEC-330 in some of their technical documentation. The daughterboard has mounting points for the Pentium II CPU itself plus various support chips and cache memory chips. All components on the daughterboard are normally permanently soldered in place. Previous generation Socket 7 motherboards cannot normally be upgraded to accept the Pentium II, so it is necessary to install a new motherboard.
All Pentium II processors have Multimedia Extensions (MMX) and integrated Level One and Level Two cache controllers. Additional features include Dynamic Execution and Dual Independent Bus Architecture, with separate 64 bit system and cache busses. Pentium II is a superscalar CPU having about 7.5 million transistors.
The first Pentium II's produced were code named Klamath. They were manufactured using a 0.35 micron process and supported clock rates of 233, 266, 300 and 333 MHz at a bus speed of 66 MHz. Second generation Pentium II's, code named Deschutes, are made with a 0.25 micron process and support rates of 350, 400 and 450 MHz at a bus speed of 100 MHz.