Abit SG-80 User Manual page 35

BIOS Setup
DRAM Clock/Timing Control:
Scroll to this item and press <Enter> to view the following screen:
DRAM Timing Control
Enables you to select the CAS latency time in HCLKs of 2, 2.5, or 3. The value is set
at the factory depending on the DRAM installed. Do not change the values in this
field unless you change specifications of the installed DRAM or the installed CPU.
DRAM CAS Latency:
This item controls the timing delay (in clock cycles) before the DRAM starts a read
command after receiving it.
RAS Active Time (tRAS):
This item allows you to set the amount of time a RAS can be kept open for multiple
accesses. High figures will improve performance.
RAS Precharge Time (tRP):
This is the duration of the time interval during which the Row Address Strobe signal
to a DRAM is held low during normal Read and Write Cycles. This is the minimum
interval between completing one read or write and starting another from the same
(non-page mode) DRAM. Techniques such as memory interleaving, or use of Page
Mode DRAM are often used to avoid this delay. Some chipsets require this parameter
in order to set up the memory configuration properly. The RAS Precharge value is
typically about the same as the RAM Access (data read/write) time.
3-11
User's Manual