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Cyrix and IBM 6x86MX 6x86L 6x86KV and MII Chip ID guide
Finding information on these chips is very difficult. Cyrix has been bought by VIA and datasheets are no longer available. Cyrix, IBM, ST and National all made the Cyrix line of CPUs. Each had their own marking system and ID codes for their chips. This makes Identifying them quite hard. Not to mention a single performence rating having 3 or 4 speeds and made on 3 different silicon processes. Thank goodness there werent many different packages. Cyrix 6x86 CPUs spanned 220MHz but their PR values spanned 343 (90-433).

IBM
Cyrix
PR Values Table
Raw Data Used in this Guide
Cyrix Time Line

IBM

IBM CPUs have the ID markings on top. They are a bit cryptic but once you look at them they really do make sense. Please note that a IBM 6x86MX is the same CPU as a Cyrix 6x86MX or a Cyrix M2. IBM chose not to change the name of the CPU while Cyrix did to better compare it to the Pentium II and K6-II.

IBM 6x86MX IBM 6x86L IBM 6x86

IBM26x86MX-mVcPRxxxpr

xxx = Performance Rating

m = Multiplier
A = 2.0
B = 2.5
C = 3.0
D = 3.5

p = package
G = 296 pin Gold plate
H = 296 pin Black Top
P = PPGA

c = core voltage
A = 2.9V
B = 3.0V
C = 3.1V

r = mask revision
A =A-step
B = B-step
C = C-step
D = D-step
E = E-step
F = F-step

IBM26 6x86L-mVcPxxxpr

xxx = Performance Rating

m = Multiplier
2 = 2.0
3 = 3.0

c = Core Voltage
A = 2.8Volts

p = Package
G = 296 pin CPGA

r = Revision
A = 2.4 (G8 Process)
B = 2.5 (G8 Process)
C = 2.7 (G8 Process)
D = 3.6 (G9 Process)
E = 3.7 (G9 Process)

IBM26 6x86-mVcPxxxpr

xxx = Performance Rating

m = Multiplier
2 = 2.0
3 = 3.0

c = Core Voltage
2 = 3.3 Volts
7 = 3.52Volts

p = Package
G = 296 pin CPGA

r = Revision
A = 2.4 (G8 Process)
B = 2.5 (G8 Process)
C = 2.7 (G8 Process)
D = 3.6 (G9 Process)
E = 3.7 (G9 Process)

Cyrix

Cyrix CPUs are even harder to identify. They follow the same PR scheme as IBM but the codes are harder to understand. the ID code for a Cyrix is located on the BOTTOM of the chip on all but the black top CPUs and Mobiles. Cyrix CPUs were produced on .35, .30, .25 and .18 micron processes. Quite often a single PR will be made in no less then 3 process technologies and 2 speeds with 2 bus speeds. All 6x86MX and M2 CPUs are 2.9 Volt. The exception to this is that all .18 micron M2s are 2.2 Volts.

National Produced MII
Black Top and Late Model MII
(All are made by National)
SGS-Thomsan

6x86

6x86L

6x86MX

Liscensed MII

Later Model

Black Top
GPFDMYWWL
G IBM
P Process (M = Mask Revision)
 
5 .65u 3 Layer      
    M 7 1.7
8 .65u 5 Layer      
    M 2 2.3
      3 2.4
      4 2.5
      5/E 2.6
      6 2.7
9 .65u 5 Layer M A 3.7
      B 3.8
E .35u 5 Layer M 7 5.7
      8 5.8
      9 5.9
F .25u 6Layer M F 6.1
      J 6.5
      K 6.6
K .25u 6 Layer M L 6.7
      M 6.8
M .25u 6 Layer + M M 6.9
         
A 6x86L .35u M 3 4.3
         
F Fab
 
D Burlington, Vt
L East FishKill, NY
K Bromont, Quebec
Q Shiga, Japan
D Die Run Code (1 or 2 chars)
Y Year
 
5 1995
6 1996
7 1997
8 1998
WW Week
L Lot Code (1 or 2 chars)
   
   
FPALLYWWDD
F Fab
 
V South Portland, ME
R Santa Clara, CA
P Process
 
1 ??
2 ??
7 .25u
B .18u
A Assembly Plant
  S Singapore
LL Lot Code
Y Year
 
8 1998
9 1999
0 2000
WW Week
DD Die Run Code
   
   
   
3PAFMYWWDD
3 National
   
P  
   
A Assembly Plant
 
S Singapore
G ??
F Fab
 
C South Portland, ME
F Santa Clara, CA
E Arlington, TX
M Unknown
Y Year
 
8 1998
9 1999
0 2000
WW Week
DD Die Run COde
   
   
   

 

FFFFG*PYWWD
G is optional
FFFF Fab
 
TB70 Carrollton, TX
AB70 Phoenix, AZ
G Unknown
   
P Process
 
8 .65u 5 Layer
9 .65u 5 Layer
Y Year
 
6 1996
7 1997
WW Week
D Die Run Code

PR Values

PR Rating Bus
(MHz)		 CPU Core
(MHz)		 Clock
Multiplier
PR90 40 80 2x
PR100 40 80 2x
PR120 50 100 2x
PR133 50 100 2x
PR133 55 110 2x
PR150 60 120 2x
PR150 50 125 2.5x
PR166 66 133 2x
PR166 55 138 2.5x
PR166 50 150 3x
PR166 60 150 2.5x
PR200 75 150 2x
PR200 55 165 3x
PR200 66 166 2.5x
PR200 60 180 3x
PR233 75 188 2.5x
PR233 66 200 3x
PR233 83 166 2x
PR266 66 233 3.5x
PR266 75 225 3x
PR266 83 208 2.5x
PR300 75 225 3x
PR300 66 233 3.5x
PR333 83 250 3x
PR350 83 250 3x
PR366 100 250 2.5x
PR400 95 285 3x
PR433 100 300 3x


If you know of any more Cyrix ID info etc. Please e-mail me and I will add it

 

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