Disk management shows different drive capacity

[Fernando Suarez Ornani]

Hi

I have 2 WDC WD10EARS-00Y5B1. They were part of a defunct 3-drive mixed RAID (part R0, part R5) from a Inter ICH9R controller. One of the drives was killed.
I've put both drives in order to do some RAID partitioning from Windows (Win 8). First time accessing the system the disk manager detected RAW data on one of them so I deleted the partition.
The strange thing is, to my surprise, that I'm having a little difference in the capacity of the drives. One is 931.39GB and the other is 931.51GB.
Why is that and how can I change this?

?

 

[Hawkeye22]

If you use diskpart's "clean" command on both drives, do they show the same size then?

 

[Fernando Suarez Ornani]

Sorry, the problem was that one was MBR and the other GPT...