Spread Spectrum Clocking is a way to lower electromagnetic interference or EMI. This is important for storage solutions that are required to pass FCC and other agency certifications. All current Serial ATA disk drives implement SSC (some allow you to turn this feature on/off). However, some older SATA drives do not implement SSC. All Sonnet Serial ATA host adapter cards support SSC but will also work with disk drives that do not.
This condition occurs when the System Preferences Energy Saver Put the hard disk(s) to sleep when possible checkbox is checked (on), or the Disk Sleep Timer is enabled; the Tempo-X SATA card using firmware version 1.2 does not support disk sleep.
To correct this issue, update the Tempo-X card's firmware to version 2.0 or later. Download and run the installer to add disk sleep support.
