Thats interesting, maybe there is something else that affects the hdd score.
So far with my rig I get 5.9 on everything but the cpu score. I only get 5.8 with that but I dont think you can get 5.9 without quadcore or say a 5.0ghz dual core or something.
Interesting with the raptor though. I ran the test several times on mine and got 5.6 though.