Clawhammer was one of the first Athlon 64 processor cores, supporting 1 MB of L2 cache memory and offering clock speeds between 2.0 and 2.4 GHz. We used an Athlon 64 FX-53, but the Athlon 64 4000+ uses exactly the same silicon. Clawhammer was a 130-nm processor. The Newcastle core had only 512-kB L2 cache and ran at between 1.8 and 2.4 GHz (3000+ to 3800+), but also was a first-generation Athlon 64 130-nm part. Both Clawhammer and Newcastle carried the CG stepping.

The 90-nm generation consisted of the Winchester (D0 stepping, 1.8 to 2.2 GHz), Venice (E3, E6 steppings, 1.8 to 2.4 GHz) and San Diego cores (E4, E6 steppings, 2.2 to 2.4 GHz).