Asus p4p800s User Manual page 58

Configure DRAM Timing by SPD [Enabled]
When this item is enabled, the DRAM timing parameters are set according to the
DRAM SPD (Serial Presence Detect). When disabled, you can manually set the
DRAM timing parameters through the DRAM sub-items.
Configuration options: [Disabled] [Enabled]
Memory Acceleration Mode [Auto]
This field when [Enabled] minimize latencies from CPU to memory to boost system
performance. Configuration options: [Auto] [Enabled]
Setting to [Enabled] may cause the system to become unstable! If this
happens, revert to the default setting [Auto].
DRAM Idle Timer [Auto]
Configuration options: [Infinite] [0T] [8T] [16T] [64T] [Auto]
DRAM Refresh Mode [Auto]
Configuration options: [Auto] [15.6 uSec] [7.8 uSec] [64 uSec] [64T]
If the system becomes unstable after changing the settings of any of the above
items, revert to the default settings.
The following sub-items appear only when the item Configure DRAM Timing
by SPD is set to Disabled.
DRAM CAS# Latency [2.5 Clocks]
This item controls the latency between the SDRAM read command and the
time the data actually becomes available. Configuration options: [2.0 Clocks]
[2.5 Clocks] [3.0 Clocks]
DRAM RAS# Precharge [4 Clocks]
This item controls the idle clocks after issuing a precharge command to the
DDR SDRAM. Configuration options: [4 Clocks] [3 Clocks]
[2 Clocks]
DRAM RAS# to CAS# Delay [4 Clocks]
This item controls the latency between the DDR SDRAM active command and
the read/write command. Configuration options:
[4 Clocks] [3 Clocks] [2 Clocks]
DRAM Precharge Delay [8 Clocks]
Configuration options: [8 Clocks] [7 Clocks] [6 Clocks] [5 Clocks]
DRAM Burst Length [4 Clocks]
Configuration options: [4 Clocks] [8 Clocks]
2-20 Chapter 2: BIOS information