Acer ASPIRE M5910(G) Service Manual page 29

Frequency/Voltage Control
Parameter
Clock to All DIMM/PCI
Spread Spectrum
Chapter 2
Description
Enables or disables control the clock to all DIMM/PCI
Enables or disables the reduction of the mainboard's EMI.
Note: Remember to disable the Spread Spectrum feature if you are
overclocking. A slight jitter can introduce a temporary boost in clock
speed causing the overclocked processor to lock up.
Option
Enabled
Disabled
Enabled
Disabled
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