More on the Xbox CPU


By Simone Scuderi

Date: December 6th, 2001

Giving a look to your XBox article I signed the S-Spec in the photo you did to the XBox; the code (SL5SN) is used by Intel to identify a sub-family.
Different chips using the same base design use similar S-Spec number.
Giving a look into intel home site I was unable to find the proper chip but I found all Celeron 733 specs:

I rearranged the row order, now they are in this format: Type / Distribution / S-Spec / Stepping / CPUID / Cache / Notes

Celeron 733 / OEM / SL5SP / BD0 / 068A / 128 / 10,12,13,14
Celeron 733 / Boxed / SL5SK / PD0 / 068A / 128 / 10,12,13,15
Celeron 733 / OEM / SL5SS / PD0 / 068A / 128 / 10,12,13,15

(from http://www.intel.com/support/processors/sspec/micp.htm)

These chips use all the same S-Spec radix (SL5S) and this radix is common only to Celeron running at 733, even Mobile Pentium 3 have a different S-Spec radix (only the SL5 part is common).
The notes as reported from Intel are:

10: .18 micron architecture
12: requires 1.7 Volt
13: 133MHz Bus speed

14 and 15 only differ FC-BGA (ball grid array) from FG-PGA (pin grid array).

Due to the document date some newer chip may not be included but all the Celeron 733 showed works at 133MHz FSB and all uses a .18 construction process. It is possible that Intel made a particular Celeron but keep in mind that the S-Spec isn't too different so probably it's only a newer version, maybe with some minor improvement. I don't know if there is some difference from any other Mobile Celeron but I think it's very difficult due to the need of making a new master (a new master should involve a completely different S-Spec.

For example give a look at the following:

Celeron 500 / OEM / SL43R / PB0 / 0683 / 128 / 1,4,7,10
Celeron 500 / OEM / SL4JU / PC0 / 0686 / 128 / 1,4,7,10

These chips have some different internal schematics as the Stepping says but externally are identical and, by consequence the S-Spec are quite different...

To provide another proof give a look at the following:

Celeron 800A / OEM / SL5SQ / BD0 / 068A / 128 / 10,12,13,14
Celeron 800A / OEM / SL5ST / PD0 / 068A / 128 / 10,12,13,15
Celeron 933 / Boxed / SL5SK / PD0 / 068A / 128 / 10,12,13,15
Celeron 933 / OEM / SL5PY / PD0 / 068A / 128 / 10,12,13,15

We may notice that the SL5S model is used also on all 800 MHz and the Boxed 933 versions while the OEM 933 use another design (that appear also for the 900 MHz version). Is clear that SL5S is an older/slower design used for slower CPU's while for upper class CPU the newer SL5P is used.

This proof that our XBox chip, SL5SN is done from the SL5S family and probably it only has some minor difference from the PC's version.

I hope this is useful to you.

(I envy you, I have to wait until march for a XBox and the cost will be higher in Europe...)



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