You have to understand where this chip comes in AMD's plans. It's a successor to the San Diego chip, with 1MB L2 cache, which samples in the second half of this year and will be produced in the first half of next year. That's a successor to the Clawhammer 939 pin with 1MB cache that forms the flagship of AMD's Athlon FX family.
Winchester, the Athlon 64 939 pin 512K chip at 90 nanometres will ship in the second half of this year.
So to reprise, in Q2 05 we'll see the FX57, which follows the FX55, which in turn is the successor to the FX53. The FX55 is slated to emerge around Q4 of this year. AMD will continue to position the FX* family against Intel's Extreme Edition - so price changes will probably march in step.