3-12
MS-7135 ATX Mainboard
back, which takes twice the amount of time. W ith current DRAM chip densities,
this is not yet an issue, however, with the upcoming densities of greater than 1
Gbit/chip, tRFC will have to be roughly 2 x tRC. Setting options: [Auto], [9T] ~
[24T].
Row to Row delay (Trrd)
W hen the
Timing Mode
is set to [Manual], the field is adjustable. This BIOS
feature specifies the minimum amount of time between successive ACTIVATE
commands to the same DDR device. The shorter the delay, the faster the next
bank can be activated for read or write operations. However, because row
activation requires a lot of current, using a short delay may cause excessive
current surges. Setting options: [Auto], [2T] ~ [4T].
Write recover y time (Twr)
W hen the
Timing Mode
is set to [Manual], the field is adjustable. It specifies
the amount of delay (in clock cycles) that must elapse after the completion of a
valid write operation, before an active bank can be precharged. This delay is
required to guarantee that data in the write buffers can be written to the
memory cells before precharge occurs. Available settings: [Auto], [2T], [3T].
Write to Read delay (Twtr)
W hen the
Timing Mode
is set to [Manual], the field is adjustable. This item
controls the W rite Data In to Read Command Delay memory timing. This consti-
tutes the minimum number of clock cycles that must occur between the last
valid write operation and the next read command to the same internal bank of
the DDR device. Available settings: [Auto], [1T], [2T].
Read to Write delay (Trwt)
W hen the
Timing Mode
is set to [Manual], the field is adjustable. This setting
controls the Read-to-W rite turnaround time. It specifies the Number of memory
cycles after a read until a write can be done without running into bus contention
and other issues. Setting options: [Auto], [1T] ~ [6T].
Refresh period (Tref)
W hen the
Timing Mode
is set to [Manual], the field is adjustable. Select the
period required to refresh the DRAMs, according to DRAM specifications. Set-
ting options: [Auto], [1x1552 Cycles] ~ [4x4672 Cycles], [128].
User Config mode
The BIOS will automatically control the following four settings if this function is
set to [Auto]. If you set this field to [Manual], the following fields will be selectable.
Setting options: [Auto], [Manual].
1T/ 2T M emory Timing
When the
User Config mode
is set to [Manual], the field is adjustable. This field
controls the SDRAM command rate. Selecting [1T] makes SDRAM signal con-
troller to run at 1T (T=clock cycles) rate. Selecting [2T] makes SDRAM signal
controller run at 2T rate. Setting options: [1T], [2T].
