Could be caused by too much traffic on the PCI bus. If the system is using an ATTO SCSI card, here's a method to adjust the throughput:1) Launch ExpressProtoolsPCI ( not ours, it's ATTO's application).2) Switch the Busses & Drives menu on Busses & Devices (1st left Window)3) Select the Drive connected on the ATTO Bus and click on the Information button on the right of the drive.4) At the bottom right of the window, switch the Sync Rate 10 MB.5) Repeat steps 3 & 4 for each drive connected on the ATTO Card.6) Quit the application, saving the configuration.