"With the advent of the AMD Athlon processor, AMD has taken 3DNow! Technology to the next level of performance and functionality. The Athlon XP processor adds 24 new instructions to the existing 3DNow! and MMX™ instruction sets. Along with the new instructions, the Athlon XP processor implements additional microarchitecture enhancements that enable more efficient operation of all these instructions, and programming may be simplified because there are fewer coding restrictions."
FULL STORY @ PUREOC (http://www.pureoc.com/AMDXP2000_1.asp)