If you read this, you will see that the lower the bin goes, the vastly higher the leakage goes as well. This means that AMD is more or less binning 65nm parts based on leakage alone, and power consumption is the overriding factor limiting the new processes ramp.
Until the firm gets the process under control, it will not be able to meet or exceed the clock speeds achieved on the 90nm process. This also has some pretty ugly implications for Barcelona's ramp, and AMD in general. It is looking like AMDs 65nm process will be about as universally loved as Intel's 90nm ones.
On the up side, if AMD can get this under control, it will have a good part with 65nm K8s and potentially Barcelonas. The question now is, when will this happen? If at all. µ