The difference is the clock speed, the 8500dv 64mb runs at 230/190 and the AIW 8500 128mb runs at 275/275. The 128mb runs at the same speed as the other 8500s but the 8500dv runs slower then the 8500LE cards.
Ill look for some benches but i dont know if i will find any.
EDIT: Just check out these benches It shows the 8500dv up against a regular 8500 (64mb) and a GF3. keep in mind the AIW 8500 128mb has more RAM then the card in the bench but that wont have a whole lot of impact on the scores.