ENCINEER - OLD CPU

Vintage CPU

Pentium Pro

I collect vintage CPU’s (central processing unit) and associated chips for fun. My collection started out by accident really. Through the 90′s I was upgrading my computer every couple of months, and so built up a wide range of CPU’s.

It’s also thanks to eBay and Yahoo UK Auctions ( anyone remember them?? ) where I found the majority of pieces in my collection. I also picked up some nice pieces in the forum of CPU World. The rest of my chips were acquired from other collectors and friends.

I focus my collection on Intel processors, specifically:

Intel 80486
Pentium
Pentium Pro

The information and exhibits I have within these processor family groups are arranged by family, speed and by sSpec. The sSpec number is also known as the specification number and SL code. It is a five character string (SL36W, XL2XL, etc.) that is printed on the processor for identification. The sSpec is typically found on the top side of the processor.

Processors within a family of the same speed can have different sSpecs. The reason is because when a processor stepping change occurs, a new sSpec is generated for that stepping. It is also true that the same stepping level can also have more than one sSpec associated with it.

A stepping is essentially a revision of the processor silicon. These are divided into two types. One type is called a full-layer stepping in which all the masks used to create the silicon can change. The other type is called a metal-layer stepping in which only the masks which are regenerated are the metal layers, allowing for fewer possible changes. Each stepping gets a different name. The usual naming convention is to change the letter of a stepping on each full-layer stepping and change the number of a stepping on the metal-layer stepping. As an example, the first full-layer stepping from A0 would typically be B0 and the first metal-layer stepping from A0 would be A1.