Do not know if there is an actual difference but, some boards clock better on certain ratios than others. My examples:
AN7 clocks better on a 6:6 ratio
NF7 clocks better on a 5:5 ratio
All my DFI's seem to clock better at 1:1
300.7 was tough to get, but I highly doubt Stelios tried to beat the system, if you will. It not his way.