How to Set your Memory Timing in BIOS

Edison

How to Set your Memory Timing in BIOS

The BIOS on your motherboard offer numerous settings to optimize your memory. These settings modify RAM functions that, while basic in nature, are often given widely different names. There are five basic settings that if set correctly can help optimize your memory. We'll briefly explain the options. We've also included examples of what the settings might be called in different BIOS versions.

NOTE: Not all BIOS menus offer all these settings.


tCL - CAS Latency (also labeled as CAS Latency Time, CAS Timing Delay) The number of clock cycles that pass from the column being addressed to the data arriving in the output register. The memory manufacturer lists the best possible setting as the CL rating.

tRCD - RAS to CAS Delay (also labeled as Active to CMD) Number of clock cycles that pass between the row address being determined and the column address being sent out. Setting this value to two clock cycles can enhance performance by up to four percent.

tRP - RAS Precharge Time (also labeled as RAS Precharge, Precharge to active) Number of clock cycles needed to precharge the circuits so that the row address can be determined.

tRAS - Row Active Time (also labeled as Active to Precharge Delay, Row Active Delay, Row Precharge Delay) Delay that results when two different rows in a memory chip are addressed one after another.

CMD - Command Rate (also labeled as CMD Rate) Number of clock cycles needed to address the memory module and the memory chip with the desired data zone. If your memory banks are full to capacity, you will have to raise this rate to two, resulting in a considerable drop in performance.

Memory timings are usually in the following order:

tCL - tRCD - tRP - tRAS - CMD

For example, our PDC1G3200LLK has a timing of 2-3-2-5-t1. This translates to the following:
tCL = 2   tRCD = 3   tRP = 2   tRAS = 5   CMD = 1




Just always remember the minimum timings for tRAS and tRC can be calculated as:

tRAS = tCL + tRCD + tRP

tRC = tRP + tRAS

Going with lower values of tRAS and/or tRC than these calculated values will not result in better performance and probably give worse results or errors (because the memory timing model is violated). That being said, there's no guarantee that you be able to go as low as these minimum values with tRAS (at whatever tCL, tRCD and tRP you've chosen). No matter what you set tRAS to, be sure to set tRC with the formula.

So the moral of the story is:
If you tweak tCL (CAS), tRCD or tRP, be sure to adjust tRAS and tRC.

gzXW

:wub:
如何在BIOS中设置你的内存时序

    主板上的BIOS提供了许多选项对你的内存进行优化。这些设置修改内存的操作

，实际相同的操作，命名却差异相当大。以下有5项基本的设置，当你设置恰当的话

，能优化你的内存。我们将简要解释一下这些选项，包括不同BIOS版本中的例子。
   
    注意：并非所有版本的BIOS提供全部的设置。


    tCL - CAS潜伏时间（也被标识为CAS等待时间，CAS时间延时）从列地址选通到

输出寄存器接收数据的时钟周期数，内存生产商列出最佳设置为CL值。
    tRCD - RAS to CAS延时（也被标识为CMD操作时间）行寻址结束到列寻址开始

的时钟周期数。设置这个值为2能提高4%的性能。
    tRP - RAS预充电时间（也被标识为RAS预充电，操作前预充电）电路预充电至

行地址能确定的周期数。
    tRAS - 行地址选通时间（也被标识为行操作至预充电周期，行操作延时，行预

充电延时）一块内存芯片中不同的两行，从一行至另一行之间寻址的延时。
    CMD - 命令循环速率。寻址内存模块与内存芯片想得到的数据存储区的时钟周

期。如果你的内存bank已经装满，你必须提高此值至2,造成的结果是性能下降相当

大。
    内存时序通常以如下次序排列：
tCL - tRCD - tRP - tRAS - CMD

    例如：我们的PDC1G3200LLK的时序为-3-2-5-t1，转换过来就如以下所示：
tCL = 2   tRCD = 3   tRP = 2   tRAS = 5   CMD = 1


有不对的地方，欢迎指出。:thumbsup:

yysina

关键在怎么设置这些数字上，要是凭经验的话不知道要废掉多少个条子了

lzc_dl

参数设置错了内存会坏吗？？

madware

is there any more detail?

apexmfg

設置錯最多電腦起不了機.不會壞條子,:p

rick.li

原帖由 yysina 于 2006-9-7 12:24 发表
关键在怎么设置这些数字上，要是凭经验的话不知道要废掉多少个条子了

从来没遇到过参数设错而损坏条子的

不死的虾虾

自己研究参数太耗时间了，清BIOS都清都手软，希望有DX把所有品牌型号的最夹参数全部研究出来:lol:

Timme

How to Set your Memory Timings on-the-flyw00t)

eddylee530

现在自用2335

eddylee530

现在自用2335