Well, if the power was removed suddenly when none of the drive is writing, you are lucky. Otherwise, you bet there will be a re-sync. In fact, prior to 1.08, the ext2 will also likely need a fsck. If you do not trust me, try it out, it is not very difficult to duplicate this one

On the 80MB/s: yes, DNS323 can sync at this rate with 7200rpm SATA2 drives. You can observe this only by getting into the box and checking out /proc/mdstat. In fact, this is one of the strength of the DNS323 SATA controller. On a typical PC with a PCI SATA controller, one can easily expect about 75MB/s re-sync with 7200rpm SATA2 drives, the bottleneck is the PCI bus.