Datasheet

Identifying Motherboards 31
Third-generation (MMX) Pentiums, released in 1997, added multimedia extensions
(MMX) to help the CPU work with graphic-intensive games. They used Socket 7 sockets, drew
+2.8V, and ran at 166MHz to 233MHz. Due to the voltage difference between the Pentium
MMX CPU and other Socket 7 CPUs, the MMX CPU required a motherboard that either was
specifically for that CPU or had a VRM that could take the voltage down to that level.
PENTIUM PRO
The Pentium Pro, released in 1995, came between the second- and third-generation Pentiums.
Physically, the Pentium Pro was a PGA-style, rectangular chip with 387 pins, using a Socket 8
socket drawing +3V. It was designed primarily for server usage, and was optimized for 32-bit
operating systems. On a 16-bit OS like Windows 3.1, the Pentium Pro ran more slowly than a
Pentium, so it failed to gain widespread consumer support.
The Pentium Pro included quad pipelining, which processed four operations at once. It
was also the first CPU to include an on-chip L2 cache. Another advantage of the Pentium
Pro was dynamic processing, which allowed it to run instructions out of order whenever it
was waiting for something else to happen.
Throttling is a term CompTIA expects you to know for the exam. With throt-
tling, you artificially reduce the amount of resources available. Although
commonly used with bandwidth to prevent one user from absorbing all the
resources on a network, it can also be applied to processors and applica-
tions. In many senses, throttling in this manner is the opposite of over-
clocking—where you attempt to get the processor to run at a speed higher
than it’s marked by using a faster bus speed or some other trick.
PENTIUM II
Intel next released the Pentium II. This chip’s speeds ranged from 233MHz to over 400MHz.
It was introduced in 1997 and was designed to be a multimedia chip with special on-chip
multimedia instructions and high-speed cache memory. It has 32KB of L1 cache, dynamic
execution, and MMX technology. The Pentium II uses an SECC to attach to the motherboard
instead of the standard PGA package used with the earlier processor types.
When released, the Pentium II was designed for single-processor-only applications. Intel
also released a separate processor, known as the Pentium II Xeon, to fill the need for multi-
processor applications such as servers. The Xeon’s primary advantage is a huge L2 cache (up
to 2MB) that runs at the same speed as the CPU. The Xeon uses a special size of SECC-style
slot called Slot 2.
Different voltages have been used for the Pentium II over its lifespan, ranging from
+2.8V to +2.0V. When you’re using a Pentium II, it’s important that the motherboard pro-
vide the correct voltage to it. This can be achieved with a VRM on the motherboard that
detects the CPU’s needs and adjusts the voltage provided.
CELERON
To offer a less-costly alternative and to keep its large market share, Intel released the Cel-
eron. In some cases, the Celeron was priced as low as half the retail price of the Pentium II.
Because it was developed after the Pentium II, it benefited from some advancements and in
86504c01.indd 31 7/25/09 6:04:16 PM