On the top capture, with only one HD, there is a weird phenomenon, already picked up by Barefeats resembling to an incomplete compatibility between the Seagate 750GB HD and the MacPro.
this problem disappear immediately when using 2 HDs in RAID 0.
As demonstrated by those capture, the software RAID feature inside OSX is really powerful, improving read/write speed proportionally to the number of HDs used in the RAID.
