I think AMD is going to try and release 65nm as early as they can this year, 65nm will bring more of a performance curve to a given platform (K8L) because there are other technologies incorporated into the fabrication process which improves performance farther, better heat control, faster switching transistors etc.
So K8L produced on AMD?s 65nm will give it even more of a boost in performance, although some articles on the net have implied that AMD if need be, can actually release the new core on its current 90nm fab.