The Register has some info on the model numbering scheme of AMD's upcoming 1,207-pin Socket F Opteron processors.
According to leaked model number guidelines published by DailyTech, "all next-generation DDR 2-based Opteron processors are dual-core" and AMD is "moving to a four-digit model number scheme".
So, the old 1xx series will become the 1xxx line-up, though unlike the 2xxx and 8xxx series, the 1xxx chips will sit on Socket AM2 connectors, the document confirms. The four-digit number scheme "can continue for up to eight generations of Opteron processors", the leaked document reveals. The first ones, since they're "second generation" Opterons will appear as 12xx, 22xx and 82xx chips.
Other documentation suggests we'll see 2.6GHz 2218 and 8218 Opterons at launch, alongside 2.8GHz 2220 SE and 8220 SE, but don't necessarily expect big jumps in performance over current 2.6GHz and 2.8GHz dual-core Opterons. The numbering scheme mentions low-power Opterons with the 'HE' suffix.