DDR2s basic clock is alot lower than DDR, enless hes falked out about £350.
And even then it could be a totaly different rig. hdd set-up & speed, obviously going to be a different CPU, un-defraged drive, graphics card memory will imppact game loading slightly, motherboard/chipset, all these things effect load times.
When i was messing about it was the same rig at different timmings, and it made no difference in anything i tried.