Abit KD7A User Manual page 45

BIOS Setup
DRAM Timing Selectable:
Four options are available: Manual
set to "By SPD", the BIOS will read the DRAM module SPD data and automatically set to the values
stored in it. If you set to "Manual", the following five items will be available to let you make
adjustments.
CAS Latency Time:
Four options are available: 1.5
(Column Address Strobe) latency time according your SDRAM specification.
Bank Interleave:
Three options are available: Disabled
your SDRAM module structure, the 4-Way setting can offer the best performance. If you choose the
wrong setting, the computer system will not run in a stable manner. For detailed information on your
SDRAM module, please ask your SDRAM module manufacturer.
Precharge to Active (Trp):
Trip timing value (Precharge time – time from precharge command to when back can be activated).
Active to Precharge (Tras):
Tras timing value = Minimum bank active time from activate to precharge of same bank.
Active to CMD (Trcd):
Trcd timing value = RAS to CAS latency + rd/wr command delay
DRAM Burst Length
DDR SDRAM modules provide a Burst mode that means an auto precharge function for programmable
READ or WRITE burst lengths of 4 or 8 locations.
This means that if we set burst length to 8, the address bus will acesss 8 bytes each cycle to precharge,
etc.
DRAM Command Rate:
Two options are available: 2T Command or 1T Command. The default setting is 2T Command. When the
host (northbridge) locates the desired memory address, it then processes the wait state of commands. Set
it to 2T Command for system compatibility or to 1T Command for system performance.
Write Recovery Time:
Two options are available: 2T or 3T. The default setting is 3T. This is the period between two write times.
DDR400 tWTR timing control
Two options are available: 1T or 2T. The default setting is 2T. This is the Internal WRITE to READ
command delay time period.
By SPD Turbo
2 2.5 3. The default setting is 2.5. You can select SDRAM CAS
2 Way 4 Way. The default setting is Disabled. Depending on
Ultra. The default setting is By SPD. When
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