The Free On-line Dictionary of Computing (30 December 2018):

Pentium II
Pentium 2

    Intel Corporation's successor to the Pentium
   Pro.

   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.

   (http://intel.com/PentiumII/).

   (1998-10-06)