Everything is connected fine, the SCSI HD is going to the internal SCSI 0 bus and the 2nd SCSI bus (1) has nothing plugged into it. I'm thinking that if I had multiple SCSI drives in the SSI chain I'd probably be able to get closer to 10MB/sec, but I'd have to do that simultaneously. It probably just doesn't go faster than 5MB/sec per SCSI device for whatever reason.

While I'm at it, I'm curious about the internal connector for the external SCSI bus. I looked for some documentation but I didn't find anything on how the internal connector and the external connector play together for bus 1. Did they put an internal connector in there for bus 1 so people could load more HDs into it instead of worrying about external gear? Maybe plugging something into there makes the external connector not work.