what most people dont know about 64-bit processors is that programs that were not designed for 64-bit i.e games, video applications, etc. will have to work twice as hard as a 32-bit like intels. although programs do seem to be becoming 64 as well as 32 compatible...
But for now Intel>AMD
EDIT: Sorry for off-topic btw Prescotts although they may have 1mb L2 Cache, dunno what your looking at for prescott's, they do tend to run hotter than a lot of other processors. If your looking to overclock and dont want to buy upgraded heatsinks/fans go with the C