标题: How to Set your Memory Timing in BIOS [打印本页] 作者: Edison 时间: 2005-11-1 12:12 标题: How to Set your Memory Timing in BIOS 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.作者: gzXW 时间: 2006-1-1 14:13 标题: 自己看了一遍，大概意思如下： :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