2 Channel PCI-X to Ultra320 SCSI, VHDCI Interface. The UL4D dual-channel Ultra320 host adapter is the perfect complement to ATTO's ExpressPCI family of high-performance SCSI host adapters for data-intensive environments. Boasting data-transfer rates of up to 640 MB/sec. and offering support for advanced PCI-X busses, the UL4D is an ideal fit for Enterprise servers and high-end workstations running high-volume, mission-critical applications such as messaging and databases.