Athlon 64 4000 and the Athlon FX-55.

AMD, a company known for its inexpensive, yet powerful processors, has
recently released the Athlon 64 4000 and the Athlon 64 FX-55. The
Athlon 64 4000 runs at a clock speed of 2.4GHz-the same as the Athlon
64 FX-53, but benchmarks at the equivelant of a Pentium 4, 4GHz. Since
a Pentium 4 4GHz processor does not yet exist, AMD starts to pull
ahead in the processor race. Even more exciting is the Athlon 64
FX-55. It runs at 2.6GHz and benchmarks quite a bit higher than the
Athlon 64 4000. These processors are not for the average consumer
though. The Athlon 64 4000 Retail Box will run you $779.00, while the
Athlon 64 FX-55 Retail Box will run you $888.00. So, these processors
may not be inexpensive, but they will give you the best performance
possible.

Athlon 64 FX-55
Athlon 64 4000
3.4GHz EE

Toms Hardware has a review of these two processors. And Intels 3.4GHz
Extreme Edition for $995, doesn't even compare in the gaming
benchmarks.

Thanks to fragger 1191 from the forums.