If the reports are correct, there might well be another reason. And that is, that despite having PR ratings for future Athlon 64 microprocessors, and despite reported problems with Intel's future Prescott chips, it's not realistic to start its desktop 64-bit family off at any speed below 2GHz, given that Intel will start that family off at high frequency speeds.
The article says AMD will introduce an Athlon 64 FX-55 at 2.4GHz (940) pins, an FX-53 2.2GHz (940) pins, a 3700+ (2.4GHz 754 pins) and a 3400+ (2.2GHz, 754), but the higher speeds probably won't appear until next year.
The launch Athlon 64 will be a 2GHz (3200+) model, the web site claims.
The German article is here. We do wish AMD would make up its mind on how these PR ratings are calculated. µ