Keith, re: there is no "Mobile Athlon 64 X2 4400+".
I did call it 'slightly hypothetical' for a reason (reading your reply I think I should have expressed myself more clearly): I talked about clocking down and volting down a DESKTOP A64 X2 4400+ to perform like a hypothetical MOBILE A64 X2 3800+. That's useful in the DTR segment.