Cisco Supervisor Engine

The Cisco Supervisor Engine is the heart of many of Cisco's switches. The Supervisor Engine has evolved several times. While it is the management segment of many routers the power of the switch is often much greater than that of the Supervisor Engine because one of features of many switches is that dozens of the functions are accelerated by ASIC.
Abridged list of features:
802.11q VLAN
Spanning Tree Protocol
Ether Channel
Jumbo Frames
(E)IGRP, OSPF, RIP (2), Static Routing
BGP, IS-IS
QOS
Some have Layer 3 & 4 Switching

Details
Supervisor Engine I
68EC040
Chassis: 2900, 2948G, 2980G, 4000, 4500, 5000, 5500, 6000, 6500, 7600
Supervisor Engine II
MIPS R4700
Chassis: 2926, 4000, 4500, 5000, 5500, 6000, 6500, 7600
Supervisor Engine II+
MIPS R4700
Cisco Express Forwarding
Chassis: 2926, 4000, 4500, 5000, 5500, 6000, 6500, 7600
Supervisor Engine III
Cisco Express Forwarding
Max DRAM: 256MB SD
Redundant Capable
Netflow accelerator card
Supervisor Engine IV
Cisco Express Forwarding
Max Flash: 64MB (supplemental Compact Flash optional)
Supervisor Engine V
Cisco Express Forwarding
Chassis: 4500
Supervisor Engine 6
Cisco Express Forwarding
Chassis: 4500 "E" Series
Supervisor Engine 32
Cisco Express Forwarding
Chassis: 6000, 6500
A low cost, reduced version of the 720
Policy Feature Card 3b
MSFC 2A?
Supervisor Engine 720
Cisco Express Forwarding
Policy Feature Card 3A, 3B, 3BXL
Chassis: 6500, 7600
MSFC1-3
Multi-Layer Switch Feature Card