I've just received a P35C-DS3R and I tested the memory wall.
I reached 737,9Mhz :http://valid.x86-secret.com/show_oc?id=207971
then my DFI P965-S, I reached 757,9Mhz with the same memory

Moreover, I measured Vdimm with Multimeter and with +0,7V (normally 2,6V), I've 2,85V