What is meant by CPU stepping?

[Garet Jax]

Hello all,

I have been doing some research into CPUs because I am a new system for myself. During my research, I have seen references to CPU steps (ie CC0, CB0) and I really don't know what they refer to. I looked for further explaination on Intel's site, but couldn't find anything.

Could someone please take the time to explain it (or provide a link to a site that explains it).

Please include which make of CPUs steps apply to (ie. Intel PIII, AMD TBird, both, neither, other, etc...). Thanks a lot.

 

[DanishGuy]

Hey Garet, nice post you started so please let me bump it for ya!


*BUMP*

 

[BadThad]

The "steppings" are slight changes made to the manufacturing processes in order to obtain better yields and achieve higher clock speeds.

 

[pm]

A stepping is a revision of silicon - to be more precise it refers to a change to the mask used to manufacture the chip. This change can for any number of different reasons: to improve bin split (frequency), to fix errata (ie. bugs), to improve yield, to solve an electrical issue and other misc. reasons.

Intel defines steppings in two forms. A letter change is a change to the complete set of masks. A number change only refers to a subset of the masks. So, A1 -> A2 is a change to just a few layers (usually metal), while B0 -> C0 is a change to all layers.

IMO, the most important point to remember about steppings is that you shouldn't mix them in a SMP (multi-processor) system.If you have one 733MHz Pentium III cB0 CPU, and you want to add in another to make a dual-processor setup, then I strongly recommend getting another 733MHz Pentium III cB0, and not putting in a 733MHz Pentium III cA2 or a cC0 instead.

Patrick Mahoney
IPF Microprocessor Design
Intel Corp.

 

[Garet Jax]

Patrick,

Thanks a ton for your post. In my own words, a CPU stepping is very similar to software versions. It is true that, for the most part, the later the stepping the better?

I am putting together a multiple processor system (ASUS CUV4X-D MB). How do I tell the stepping on a particular CPU? Will most resellers be able to tell a CPUs stepping? In your experience, are most resellers receptive to CPU stepping requests?

Again. Thanks a lot.

 

[pm]

Yes, you could think of it as a software release. But it's worth mentioning that rarely steppings are released that may have no notable diffence to the prior stepping as far as the end-user is concerned. A stepping for a yield improvement would not be noticeable at all to the home user. Software releases are almost always released for a reason that would be noticeable to the end-user.

And yes, later should always be better.


<< How do I tell the stepping on a particular CPU? >>


One way is to look at the Quick Reference Guide here - warning, it's in Adobe Acrobat format.


<< Will most resellers be able to tell a CPUs stepping? In your experience, are most resellers receptive to CPU stepping requests? >>


In my experience, they are not very receptive at all. They generally seem to consider it an irritation - the bigger the company, the more painful this is since they just want to ship the order to the warehouse and have it filled, not have the guys in the warehouse sort through the boxes one by one until they find one that matches. I have had luck with smaller companies though - especially when you say that you don't care what the stepping is as long as both processors are matched. Mwave.Com (pretty much my favorite online supplier) will do matched processor requests (grudgingly). Buy.Com won't even consider them. My best luck with stepping requests has been from Dallas Memory - but make sure you call them directly (don't place the order online). Have the quick reference sheet next to you and they will read off the codes and you can tell them when they read one that you like. They seem like a nice gang and they have an OK resellerratings score. I've dealt with them twice with no problems.

Another excellent source is the Anandtech Forum's user compuwiz1. He's got a great reputation and is a very pleasant person to deal with. He deals in CPU's and should be able to set you up with a matched set of a specific stepping. Email or PM him by searching for him with the search command above.

 

[Garet Jax]

Thanks a lot again Patrick.

I love Anandtech. There are lots of knowledgeable people and most of them are willing to share the wealth.

WooHoo!

 

[breweyez]

bump for some great info!! Thanks Patrick

 

[pm]

I'm glad you guys found it useful.

Good luck with the SMP system, Garet. That was a pretty good book, too - although Elfstones was my favorite.

 

[Garet Jax]

PM,

Really? I have had a number of people tell me the same thing about the second book. The first time I read them, Elfstones was my least favourite: wishsong was my favourite. Having read them again, I no longer have a least favourite, but my favourite is still the wishsong (Probably because of Garet Jax)

 

[pm]

Can't explain - who can explain why you like what you like? - but Elfstones is/was (it's been a while since I read them) my favorite. Wishsong is a very close second though.

 

[ryko212]

bump for an interesting topic

 

[joohang]

Another bump

 

[kw3i]

yes i too thing this is bump material

 

[Overman]

PM, Garet Jax,....have you guys read the next series of Shannara books? They were pretty good also....kinda helped me out when I was in the hospital (about 16 years ago). If not, you should read em!

BTW, I met Terry Brooks at a Barnes and Noble store a couple of months ago (Minnesota), he is an interesting guy. He read from his newest book, which sounded pretty cool.

Also asked him if anyone has approached him to make a movie outta the Shannara series...he basically said that he was waiting to see how the Tolkien movies do (coming out this summer) before he agreed to a movie being made.

Anyway...sorry this is OT.

 

[SiliconVandal]

bump

great info..

 

[billandopus]

What a sweet thread. This has always been a nagging topic that i've never remembered to search for ... and now I have the answer. Thanks guys.