Leifern: should definitely be much faster.. I'd say roughly about 10 times faster

At least I get such values on my b1260 with scsi-kit. I'd check version of 1230scsi.device and settings for your scsi devices. I'd recommend V8.5 or later for 1230scsi.device and "reselection" and "synchron" for scsi options for all devices. Especially if you have more than one device

Otherwise it could be like having "ide emulation" turned on as someone nicely said once

And you have terminated your scsi-chain correctly?