This is what the Adaptec site says about these cards (one is 32bit pci other is 64 bit pci) BELOW.
Adaptec SCSI Card 29160N [top of page]
Ultra160 SCSI performance, with easy connectivity to internal hard disk drives and external narrow SCSI devices
The Adaptec SCSI Card 29160N is tailored to the needs of small multi-user work group servers and powerful workstation users. This 32-bit PCI card gets the most out of high-performance Ultra160 SCSI internal hard drives and the widest selection of popular external SCSI devices.
Adaptec SCSI Card 29160 [top of page]
Maximum Ultra160 SCSI performance, with greatest connectivity options for internal and external hard disk drives
The Adaptec SCSI Card 29160 is tailored for the entry level to mid-range server environment. It delivers the maximum throughput for a single channel Ultra160 SCSI card by using a 64-bit PCI interface. The Adaptec SCSI Card 29160 allows for connecting Ultra160 SCSI (LVD) or legacy hard disk drives, internally and externally.
I would make sure any drives you have are ultra160.
Good Luck...