From Federico Biancuzzi’s “John the Ripper 1.7, by Solar Designer“:
John the Ripper 1.7 also improves on the use of MMX on x86 and starts to use AltiVec on PowerPC processors when cracking DES-based hashes (that is, both Unix crypt(3) and Windows LM hashes). To my knowledge, John 1.7 (or rather, one of the development snapshots leading to this release) is the first program to cross the 1 million Unix crypts per second (c/s) boundary on a general-purpose CPU. Currently, John 1.7 achieves up to 1.6M c/s raw performance (that is, with no matching salts) on a PowerPC G5 at 2.7 GHz (or 1.1M c/s on a 1.8 GHz) and touches 1M c/s on the fastest AMD CPUs currently available. Intel P4s reach up to 800k c/s. (A non-public development version making use of SSE also reaches 1M c/s on an Intel P4 at 3.4 and 3.6 GHz. I intend to include that code into a post-1.7 version.)