using a windows tool i got this results:
No one's asked what file system will be going on this RAID array? That can have a large impact on the best stripe size for the array.
FWIW, I'm not aware of any free-as-in-beer Linux file systems that have a block size larger than 4K. Maybe btrfs does, but I don't think that's really ready to use yet, although I'll admit I haven't been following btrfs progress closely.
i will be using ext3 most likelly