IBM 440 - Manual (Page 28)

14 IBM ^ xSeries 440 Planning and Installation Guide
This increases the performance of the frontside bus without the difficulty of
high-speed clock signal integrity issues. The end result is an effective burst
throughput of 3.2 GBps, which can have a substantial impact, especially on
TCP/IP-based LAN traffic.
Hyper-Threading
Hyper-Threading technology enables a single physical processor to execute
two separate code streams (threads) concurrently. To the operating system, a
processor with Hyper-Threading appears as two
logical processors, each of
which has its own architectural state - that is, its own data, segment, and
control registers and its own advanced programmable interrupt controller
(APIC).
For example, Figure 1-9 shows a 16-way x440 complex running Datacenter
Server with Hyper-Threading enabled.
Figure 1-9 Datacenter sees 32 processors when Hyper-Threading is enabled on a 16-way configuration