SATA Spread Spectrum

Common Options : Down Spread, Disabled

Quick Review

All clock signals have extreme values (spikes) in their waveform that create EMI (Electromagnetic Interference). This EMI interferes with other electronics in the area. There are also claims that it allows electronic eavesdropping of the data being transmitted.

This BIOS feature controls spread spectrum clocking of the Serial ATA (SATA) interface.

When set to Down Spread, the motherboard modulates the Serial ATA interface's clock signal downwards by a small amount. Because the clock signal is modulated downwards, there is a slight reduction in performance. The amount of modulation is not revealed and depends on what the manufacturer has qualified for the motherboard. However, the greater the modulation, the greater the reduction of EMI and performance.

When set to Disabled, the motherboard disables any modulation of the Serial ATA interface's clock signal.

Generally, frequency modulation via this feature should not cause any problems. Since the motherboard only modulates the signal downwards, system stability is not compromised. However, spread spectrum clocking can interfere with the operation of some SATA devices. If you encounter problems with your SATA devices, try disabling this feature.

If you have electronic devices nearby that are affected by the EMI generated by your motherboard, or have sensitive data that must be safeguarded from electronic eavesdropping, enable this feature. Otherwise, disable it to remove even the slightest possibility of stability issues.