MSI Wind Board 230 - Manual (Page 49)

3-19
BIOS Setup
CAS# Latency (CL)
When the Configure DRAM Timing by SPD sets to [Manual], the field is
adjustable. This controls the CAS latency, which determines the timing delay (in
clock cycles) before SDRAM starts a read command after receiving it.
tRCD
When the Configure DRAM Timing by SPD sets to [Manual], the field is
adjustable. When DRAM is refreshed, both rows and columns are addressed
separately. This setup item allows you to determine the timing of the transition
from RAS (row address strobe) to CAS (column address strobe). The less the
clock cycles, the faster the DRAM performance.
tRP
When the Configure DRAM Timing by SPD sets to [Manual], this field is
adjustable. This setting controls the number of cycles for Row Address Strobe
(RAS) to be allowed to precharge. If insufficient time is allowed for the RAS to
accumulate its charge before DRAM refresh, refresh may be incomplete and
DRAM may fail to retain data. This item applies only when synchronous DRAM is
installed in the system.
tRAS
When the Configure DRAM Timing by SPD sets to [Manual], this field is
adjustable. This setting determines the time RAS takes to read from and write to
memory cell.
FSB/DRAM Ratio
This item will allow you to adjust the ratio of FSB to memory.
Auto Disable DRAM/PCI Frequency
When set to [Enabled], the system will remove (turn off) clocks from empty DIMM and
PCI slots to minimize the electromagnetic interference (EMI).
Spread Spectrum
When the mainboard ’s clock generator pulses, the extreme values (spikes) of the
pulses create EMI (Electromagnetic Interference). The Spread Spectrum 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,
set to Enabled for EMI reduction. Remember to disable Spread Spectrum if you are
overclocking because even a slight jitter can introduce a temporary boost in clock
speed which may just cause your overclocked processor to lock up.