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.
When attempting to connect a Sonnet Tempo eSATA locking cable to a Tempo SATA E4P card in an Xserve, the locking connector housing may not fit in the tight space at the rear of the Xserve. To properly connect the cable, simply remove the locking housing from the connector end (two screws) and it will fit.