Change of model nomenclatures

The model numbers of the new line of processors was changed from the PR system used in its predecessors, the Athlon 64 X2. The new model numbering scheme, for later released Athlon X2 processors, is a four digit model number with different family indicator as the first number ^[3], while Sempron remained using the LE prefix, as follows:

Series number

Processor series	Indicator
Phenom quad-core (Agena)	9
Phenom triple-core (Toliman)	8
Athlon dual-core (Kuma)	6
Athlon single-core (Lima)	1
Sempron single-core (Sparta)	1

SOURCE :- WIKI