DS923+ running slow

Since the last update, my 923+ has been dog slow. 25-30 seconds to get to a login screen and then another 30 seconds to get to the desktop after logging in. It seems to be constantly indexing files even though the files rarely change. I have a MacBook Pro and an iMac backing up to it, but again, those devices rarely have changed files. Can I (or should I) limit file indexing? It's on a gig network and on the same switch as my iMac. CPU and Memory usage are both below 20%, so I think it's just the drives that are constantly being hammered by the indexing.