Since the launch of the Athlon 64 processors, AMD has introduced up to three different pin packaging based on the Athlon 64 technology. Users are advised to ensure the kind of processor they purchase from the stores is correctly tailored for the motherboard. Even a single pin difference is unacceptable and in case you're wondering, the answer is, NO - you cannot remove one pin from a Socket-940 processor to convert it into a Socket-939 compatible part.
All new processors based on the Socket-939 packaging will come in a new box packaging and they can be easily recognizable. The box is easier to open and inspect and it's no longer based on the difficult-to-remove plastic packaging that AMD use with all their current processors, including the Socket-754 Athlon 64 processors. The processor's part and model number can be easily seen on the clear plastic window located on the box front, as shown in the picture below:-
New Socket-939 processors now come in a new box packaging (Left to right: AMD Athlon 64 FX and AMD Athlon 64). You can check the processor's model number without opening the box via the viewing window located on the box front.
If you really need to be sure of what you're purchasing, you can read the part number off the processor's metal lid and decode them in the following manner.
A typical processor model number engraved on the processor's metal lid.
Processor Part Number Definitions
Brand
ADA = AMD Athlon 64 Desktop processor
AMA = Mobile AMD Athlon 64 processor
SDA = AMD Sempron processor
Model Number*
2800+ = 1.8GHz, 512KB L2, 754-pin
3000+ = 2GHz, 512KB L2, 754-pin
3200+ = 2GHz, 1MB L2, 754-pin
3200+ = 2.2GHz, 512KB L2, 754-pin
3400+ = 2.2GHz, 1MB L2, 754-pin
3400+ = 2.4GHz, 512KB L2, 754-pin
3500+ = 2.2GHz, 512KB L2, 939-pin
3700+ = 2.4GHz, 1MB L2, 754-pin
3800+ = 2.4GHz, 512KB L2, 939-pin
FX51 = 2.2GHz, 1MB L2
FX53 = 2.4GHz, 1MB L2
Package
A = 754 Pin Lidded Organic micro-PGA
B = 754 Pin Lidless Organic micro-PGA
C = 940 Pin Ceramic micro-PGA
D = 939 Pin Organic micro-PGA
Operating Voltage
E = 1.50V
I = 1.40V
Case Temperature
P = 70°C
X = 95°C
L2 Cache Size
3 = 256KB
4 = 512KB
5 = 1MB
Part Definition
AK = Rev. C0
AP = Rev. C0
AR = Rev. CG
AS = Rev. CG
AT = Rev. CG
AX = Rev. CG
AW = Rev. CG
* Model numbers listed here are for AMD Athlon 64 desktop parts only. Does not include Mobile and Sempron processors.
As you can see above, the various model numbers offered by AMD can be quite confusing. We're sure the complexity will increase when AMD begins to introduce more Athlon 64 processors into the market in the near future. So, make sure you know how to identify the part number before you make your way down to the store. For those in the habit of purchasing used parts, the table above should help you determine exactly what the seller is offering. To get yourself updated with the latest part numbers, download AMD's latest datasheet at this link
(Adobe Arobat Reader needed).
