BIOS Setup
3-29
Frequency/Voltage Control
Auto Detect DIMM/PCI Clk
To reduce the occurrence of electromagnetic interference (EMI), the BIOS de-
tects the presence or absence of components in DIMM and PCI slots and
turns off system clock generator pulses to empty slots. The settings are:
Ena-
bled, Disabled
.
Spread Spectrum
When the motherboard’s clock generator pulses, the extreme values (spikes)
of the pulses creates EMI (Electromagnetic Interference). The Spread Spec-
trum function reduces the EMI generated by modulating the pulses so that the
spikes of the pulses are reduced to flatter curves. If you do not have any EMI
problem, leave the setting at
Disabled
for optimal system stability and
performance. But if you are plagued by EMI, setting to
Enabled
for EMI
reduction. Remember to disable Spread Spectrum if you are overclocking be-
cause even a 0.25% jitter can introduce a temporary boost in clockspeed of
25MHz (with a 1GHz CPU) which may just cause your overclocked processor
to lock up.
CPU Clock
This setting specifies the clock frequency of CPU host bus (FSB) and provides
a method for end-users to overclock the processor accordingly.
