Windows RAID will be extremely slow when resynchronizing

A while ago I was called in to look at a server that was performing very slowly. Disk-bound operations were primarily affected. This server uses Windows RAID for redundancy and the mirror was in the process of resynchronizing. (It had recently lost power unexpectedly.) I suspect it was checking the entire volume for consistency, which uses a lot of I/O and slows down everything else trying to use the disk.