Introduction

Overclocking fever!

From time to time we like to take a look at the overclocking potential of a given processor. Since the 500E and 550E have already built a well-deserved reputation for overclocking, (For reference, our 500E runs like a charm at 733MHz) we decided to take a look at the next highest clock speed in the Intel lineup, the 600E.

With all the price cutting from Intel and AMD, 600E's can now be found for less than $240. This makes the 600E extremely affordable and only about $50 more than the 550E. Is the extra money worth it? Does the higher multiplier present on the 600E really make it easier to overclock? Those were just a few of the questions we were asking when we began preparing for this article. Let's explain the basics first before we get into the results though.

What's a 600E?

If you've shopped for a Pentium III processor recently you've been exposed to the new designations used by Intel to identify the various models in the Pentium III family. Uneducated shoppers looking for a Pentium III at 600MHz or below must be especially careful: similar designations are used for two totally different processor cores!

On one hand, you have the traditional "Katmai" Pentium III built on a 0.25-micron process and featuring 512KB L2 cache running at half the speed as the processor core. These are the original Pentium III processors Intel released last year that include Intel's new Streaming SIMD Extensions, also referred to as SSE. Offered in clock speeds ranging from 450MHz to 600MHz, Katmai was the primary Pentium III processor Intel offered throughout last year until their next Pentium III core, codenamed "Coppermine" was released.

"Coppermine"

Released in October of last year, Coppermine Pentium III processors are built on Intel's more advanced 0.18-micron process technology. With the shift to 0.18-micron, two important things occurred:

First, the amount of voltage the processor consumes is reduced to 1.65V. As a result, the processor becomes ideal for notebooks and allows higher overall clock speeds than 0.25-micron - which was pushing the limit of the core at 600MHz. In addition, with the area between transistors reduced to 0.18 microns new space was made available for Intel to add additional functions on the processor core.

Intel chose to add 256KB of Level 2 cache running at the same clock speed as the processor core. To keep the processor fed with data, the cache bus was increased from the 64-bit Level 2 (L2) cache interface present on Katmai and Celeron, to 256-bits for Coppermine.

Another feature added to the Coppermine Pentium III core are 4 new writeback buffers, 6 fill buffers, and 8 bus queue entries. These larger buffer sizes and bus queue entries speed the flow of information passed from the system bus to the processor.

Although the amount of L2 cache was reduced on Coppermine overall performance increases. As the clock speed of the processor rises, the performance gain of L2 cache running at the same speed as the processor core increases by a wider margin.