Intel moves beyond megahertz

Over the past few years the traditional clockspeed based marketing of
processors has been becoming less and less relevant. Both the Pentium 3 and
the Thunderbird-cored Athlon CPUs delivered equivalent levels of performance
for their speeds. However things changed when Intel introduced its NetBurst
architecture in the form of the Pentium 4.

Benchmark tests of the Pentium 4 showed it being slightly outperformed by
the lower speed Athlon CPUs, and this equality of performance despite an
ever increasing difference in clock speeds, has continued ever since.

To combat this AMD introduced its 'PR rating' scheme in late 2001. This
marked a move away from clockspeed based model names towards a performance
based ranking system. This was a bold move and generated a lot of flack from
consumers and competitors alike, but it worked.

It comes down to a concept called instructions per clock (IPC). This refers
to the amount of data that can be processed during each clock cycle. The
Pentium 4 uses an architecture called NetBurst, which was designed to scale
in speed over many years, the side effect being that it can execute less
instructions per clock than AMD's Athlon processors or even Intel's own
Pentium-M processors. This means that Intel needs to run the processor at a
higher speed to get the same performance.

To combat this growing disparity, especially between the Pentium 4 and the
Pentium-M Intel has decided to bring in a numbering system. This is not a
performance based system, rather it is a marketing strategy to target
average consumers. Clock speeds will still be advertised freely, but the
model numbering will mean we no longer need to deal with arcane suffixes
used to differentiate between processors that run at the same speed but have
different cache sizes or front side bus speeds.

Intel is breaking its products into three streams, and allocating three
digit numbers for each model. Celeron and Celeron-M processors will take the
form of 3xx, the Pentium 4 will use 5xx and the Pentium-M 7xx. A higher
number will not necessarily mean more raw performance as they will be
assigned with both performance and features in mind (unlike AMD's PR
ratings).

This change is set to begin sometime around May or June this year, with the
introduction of the next generation Pentium-M CPU, currently codenamed
Dothan. At the same time Intel will begin numbering its Celeron-M line as
well.

It will then roll out onto the desktop when Intel introduces its next
generation CPU socket, dubbed LGA 775. This will happen for both the
Prescott cored Pentium 4 and the Celeron CPUs, however there are currently
no plans for the enthusiast focused Pentium 4 Extreme Edition to adopt a
model numbering system. Similarly there are no plans at the moment to use
model numbering for Intel's Xeon line of server CPUs.

-- John Gillooly