I just ordered a 16GB SanDisk 90mbs SDXC card for my V1.
I will try it in the D5100 and D7000 and see if it makes any difference. When I switched from 30 to 45mbs cards, the in camera difference was too slight to notice. The big improvement was write to computer thru card reader time.
However, the V1 Expeed 3 processor should write much faster.