My sandra score

I have benched both of my hard drives separate and my WD80 7200rpm 2MB cache is at 17,203kbps. My IBM Deathstar 60 7200rpm 2MB cache is at 31,357kbps . What happened? I thought the WD would out perform the IBM. Are these good scores for a drive of this type?

defrag, sandra can be VERY sensitive to fragmentation.