At 09:32 1/27/99 -0700, SSgt Keith B. Meidling wrote:
>Could someone please explain the difference between Pentium II, Celeron,
>and the Xeon processor chips?

The main difference is in the L2 cache that comes with each processor.
(They all have basically the same core architecture.)

The 266 and original 300 MHz Celerons had no L2 Cache. These were
relatively poor performers compared to Pentium II processors of
the same frequency. The 300a and the 333 and higher MHz Celerons have
128 KB of *on-die* (i.e., integrated on the same wafer as the core
processor) L2 cache that runs at the full core frequency of the processor.

The Pentium II has 512 KB of L2 cache *off-die* that runs at half the
core frequency of the processor.

The Xeon comes in versions that have either 512 KB, or 1 MB, or 2 MB
of *off-die* L2 cache that runs at the full core frequency.

For desktop applications, comparing Celeron and Pentium II processors
of the same speed, the fast but smaller L2 cache of the Celeron can
allow it to perform on a par with the Pentium II with its slower but
larger L2.

The larger and faster cache of the Zenon seems not to be a huge
advantage (only a few percent over the Pentium II) except in server
type situations where much larger amounts of data make the large fast
L2 cache of the Xenon a significant factor.

Another difference between the processors is their scalability (ability
to do multiprocessing). Only one unmodified Celeron will work per
system. Two Pentium II processors can be used together in one
multiprocessor system.  Xenons support one, two, four, or eight way
symmetric multiprocessing.

The Celeron and Pentium II processors come in "slot one" single edge
cartridges. They are interchangeable on the same motherboard. New
Celerons will also come as chips that will fit in a 370 pin socket.
Zenons come in a larger cartridge than that of the Pentium II.
Xenons and Pentium II processors are not interchangeable.

References: <http://developer.intel.com/design/litcentr/index.htm>

Regards,
Bill

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