IBM is having problems with 90nm for the 970. That is why the Power Mac G5 has hit only 2.5 GB, instead of 3 GB as promised a year ago.
Well they're having trouble meeting 2GHz demands for Xserves as well... Keep in mind the G5s are quite a bit over engineered...
Besides, who said this is going to be a GigaProcessor derived core? None of them are 2-issue..