Spread Spectrum Clocking for WD SATA Drives

Computer use clocks to sync the flow of data as it moves from one device to another.
These clocks send out pulses, kind of like radio waves.

This energy can interfere with nearby devices.
This is called EMI.

Spread Spectrum Clocking has become a well known way to lower EMI.
This is built into the drive and can not be changed.
It speeds up and slows down the clock.

The change of clock speed must be allowed by other circuits involved.

Spread Spectrum Clocking only helps lower emissions to meet FCC regulations.

This does not change the speed of the drive.