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Memory Timings Explained

TRAS The TRAS timing can be typically be set to 5, 6, and 7. TRAS is a timing that has little effect on performance, but has a huge effect on the maximum stable speed your RAM can run. We recommend always using the slowest ( highest number ) TRAS setting available; usually on AMD motherboards this would be 6 or on P4 boards this would be 7.

Row Precharge Time
This item controls the number of cycles for Row Address Strobe (RAS) to be allowed to precharge. If Insufficient time is allowed for the RAS to accumulate its charge before DRAM refresh, refresh may be incomplete and DRAM may fail to retain data.  2T or 3T

RAS Pulse Width This setting allows you to select the number of clock cycles allotted for the RAS pulse width, according to DRAM specs. The lower this is set the faster RAM performance. 6T,5T

Bank Interleave This files selects 2-bank or 4-bank interleave for the installed RAM. Disabled, 2-way and 4-way.

Basically, a bank activate command can open one bank at the time and then the readout will occur after tRCD and CAS-DL. However, simultaneously, the memory controller can issue another bank activate command in the cycle after the first command was issued and, thus open the next bank. If the controller knows that the next set of data is going to be in a different bank, it can issue read commands to the next location without trashing the first bank's data burst.

Burst length This is a technique that DRAM uses to predict the address of the next memory location to be accessed after the first address is accessed. 4QW, 8QW

Command Rate This is the setting that selects the speed of the SDRAM signal controller. If set to 1T the memory controller is running in synchronization with your bus speed. 1T will increase your memory bandwidth but a LOT of memory brands will really have trouble running this at decent speeds. This setting will have to be played with a LOT while your increasing your FSB speed. It does in fact increase your memory bandwidth but will often lower your max bus speed so much that it just isn't worth using.

ECC "ECC" stands for "Error Checking and Correction". When ECC is enabled in the BIOS the memory check will take considerably longer than it does with normal RAM. you will just have to be patient. It does not show any special messages or any info telling you why it is taking so long. ECC RAM is more expensive. On a stick of RAM that has 8 modules a ninth will need to be added for error checking. on a 16 module stick 2 more modules will be added. The added modules are what increase the price. This will hinder your performance slightly and isn't needed by us. It's geared more towards the server market.This feature is similiar to parity back in the old days. Most of the BSOD's we always saw in the win9x days get healed by having ECC memory. Commonly RAM will have an error about once a month if it is being run 24 hours a day.


Written By: Martin Krohn
Date: 2-29-04
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