Windows 7: RAID setup, 7 creates 63offset on Dell workstation

For a RAID setup I put a pair of new 500 GB samsung sata2 disks in a Dell T3500 workstation with ICH10R controller . The raid (Intel RST) is to be for data only.

Following the instructions on screen results in a starting offset of 63 sectors under Windows 7 (this isn't normal is it?), 63 sector (x512bytes) offset is not to special for RAID 0 and 1 either.

The system disk has 3 partitions on it, two of them for 7 and one called OEM, using partition magic it seems the OEM partition is Fat16 with a 63 sector offset. The 7 partition starts are devisable by 4096.

Is this something to do with Dell ###

Please some advice on doing a good job for this raid setup.