Introduction

Introduction:  By JumpingJack

The computer enthusiast has had quite the treat over the past two years, Intel launched the successful Core 2 Duo, and AMD launched the Phenom processor in response.  The head to head competition has driven prices to new lows for some of the highest performing processors yet built.  However, building a processor takes enormous time, effort, resources, and validation.  Not all processors are created perfect either, some contain bugs or errata or there is room for improvement to squeeze out one higher speed bin and improve performance or power consumption.  For the beginner enthusiast, you may hear the term ‘stepping’, which simply refers to a revision of the product line.  More technically, a stepping, in this context, is a revision to one or more of the photolithographic mask(s) which is used to develop patterns on the die that ultimately create transistors and wire them up to make the chip.


The rate and number of steppings is governed by many factors and each company handles the details differently.  AMD, for example, start their stepping counts at the major release of a new family of processors, and continues the progression even through shrinks across process technologies.  For example, the last 90 nm K8 core (Windsor) had a stepping designation of F3, which produced the AM2 line of CPUs, where as the 65 nm Brisbane line was stepping G0 at introduction.  Brisbane was later revised up to G1 and was a nice improvement. Intel, on the other hand, typically starts the revision label at the beginning for an individual product and retires the product at the end of the life cycle.  Conroe, the famous Core 2 Duo, launched with a B2 stepping designation which was then revised to B3 stepping at the onset of the quad core.  B3 stepping was around for a short while when the stepping changed again to G0, which was a great improvement over it's predecessor.  Inklings of the B3 to G0 switch, and its improvements, will be seen in the review to come.





Today we are going to be looking at the new E0 stepping of Intel's Penryn line, which is a revised version of the previous C0 stepping that has been on the market for quite sometime now.  We will be comparing a new E0 stepping E8600 versus an older C0 stepping Xeon E3110 (identical to E8400).  Intel does a remarkable job of documenting their revision history, more so than one would think.  Any change to any product, no matter the detail, is published to their web site and is accessible for anyone to look through and read.  These come in the form of product change notifications or PCNs, and the database may be searched at this website.  Looking over the PCN database, Intel published the revision change for their Quad Core 9550 on July 25th, the Quad Core Xeon on August 1, and some desktop and mobile SKUs a little later.  Because Intel unified their architecture such that the same chip makes a mobile, desktop or server part it is important to read all the PCNs of each product type in order to capture every detail.  Simply slog through the PDFs and look for products that changed from C0 to E0 stepping.

Some of these changes include:

• Release of different and new packaging materials that are now halide free (addressing environmental awareness)
• New instruction extensions (XSAVE/SRSTOR)
• Support for power status indicator (unknown at this time)
• Speed path improvements enabling higher speed bins

The last one of this list is of the greatest interest, as it should hopefully mean some higher over-clocking potential.  The brief list shown here can be found in PCN108488-00, PCN108663-00, and 108660-00.

Intel also documents these changed items in spec updates, though those updates typically appear close to or just after release.  These can be found under the documentation for the processor series in question, for example www.intel.com/design/core2duo/documentation.htm will show specification updates, including errata fixed with each released stepping.  The current specifications do not list any specifics for the E0 stepping, but according to the update schedule we can expect one very soon.

Ok, so there it is, what a stepping means in terms of the usage of the term as well as some of the details that are going into this revision.  So without further ado… let’s get to overclocking.

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Index: Page 1 - Introduction Page 2 - Let's meet the competitors: E8600 E0 vs. E8400 C0 Page 3 - Benchmarks and Settings Page 4 - Stock vCore Overclocking Page 5 - 1.4v vCore Overclocking Page 6 - CPU Intensive Benchmarks Page 7 - Graphics and Gaming Benchmarks Page 8 - Conclusions Page 9 - Update 9/29/08