Overrated?! By all means, the AMD 64s are one of the most underrated proccesors of all time, by people confused by whole 64 bit scheme.
The Athlon 64s are some of the fastest proccesors availible of the market right now, for a huge number of reasons. The 64 bit compatiblility is a large part of it, but let's look at the 32 bit side of things.
Hypertransport 2000MT/s transfer rates, built in memory controllers, successful 90nm cores, and lower clocked yet faster cores are all huge benefits to Athlon 64s, over any other proccesor.
The Althon FX 64 proccesors even out do the Athlon 64 proccesors, twice the cache size, higher clock frequencies, an unlocked multiplier These proccesors are not overrated, they are just plain fast.
I well admit the price is a downpoint, but that is something that all new hardware has in common, it's all horribly overpriced.
But completely disregarding the whole price dillema, the FX series totally outperforms the Athlon 64 series, which are already incredible proccesors. The FX proccesors are some of the fastest and most unrivaled proccesors on the market right now, high price or not.