Tyan Computer GX21 - Manual (Page 103)

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Auto Detect DIMM / PCI Clk
This BIOS feature determines whether the BIOS should
actively reduce EMI (Electromagnetic Interference) and
reduce power consumption by turning off unoccupied or inac-
tive expansion slots.
When enabled, the BIOS will monitor AGP, PCI and memory
slots and turn off clock signals to all unoccupied and inactive
slots.
When disabled, the BIOS will not monitor AGP, PCI and
memory slots. All clock signals will remain active even to
unoccupied or inactive slots.
It is recommended that you enable this feature to save power
and reduce EMI.
The choices are:
Enabled / Disabled
Spread Spectrum
This BIOS feature allows you to reduce the EMI of your moth-
erboard by modulating the signals it generates so that the
spikes are reduced to flatter curves. It achieves this by vary-
ing the frequency slightly so that the signal does not use any
particular frequency for more than a moment.
In most conditions, frequency modulation via this feature
should not cause any problems. However, system stability
may be slightly compromised in certain situations. For exam-
ple, this BIOS feature may cause improper functioning of tim-
ing-critical devices like clock-sensitive SCSI devices.
Spread Spectrum can also cause problems with overclocked
systems, especially those that have been taken to extremes.
Even a slight modulation of frequency may cause the proces-
sor or any other overclocked components of the system to
fail, leading to very predictable consequences.
Therefore, it is recommended that you disable this feature if
you are overclocking your system. The risk of crashing your
system is not worth the reduction in EMI. Of course, if EMI
reduction is important to you, enable this feature by all means
The choices are:
Enabled / Disabled