I recently removed the drives from a system configured with Raid 1 array (non-boot, on a MSI P35D3 mobo). I stuck the drives, one by one, into another system so I could reformat them and reuse them independently. While doing this, I noticed that the drives had different data on them. One of the drives had current data and the other drive had data a couple months old.
There were no error messages present when booting the system before removing the drives. I also ran diagnostics on them (independently, from the 2nd system) and they both report no errors. Is it ever expected that the data on the drives is not identical without a hardware problem?
I'm half tempted to put the array back together and do some further investigation, but since I don't plan to use this setup anymore I'd rather not spend a bunch of time on this just to satisfy my curiosity.