Memory Timings. Have I correctly applied them?

[apoth99]

Hello, when my computer shipped from the supplier the following settings were applied using the "AUTO" feature in my motherboard, which is a GA-965P-S3.

CAS Latency Time: 5
DRAM RAS# to CAS# Delay: 5
DRAM RAS# Precharge: 5
Precharge Delay(tRAS): 18
ACT to ACT Delay(tRRD): 3
Rank Write to READ Delay: 3
Write to Precharge Delay: 6
Refresh to ACT Delay: 42
Read to Precharge Delay: 3

My memory is Corsair XMS2 (TWIN2X2048-6400C4) Dual Channel kit 2x 1GB PC6400 DDR2 (800Mhz) Memory CL4-4-4-12 (http://www.corsairmemory.com/_datasheets/TWIN2X2048-6400C4.pdf)

As I understand it the "4-4-4-12" part of that lingo refers to memory timing. Specifically the section I have bolded above. My logic is that I should change the above settings to the following below:

CAS Latency Time: 4
DRAM RAS# to CAS# Delay: 4
DRAM RAS# Precharge: 4
Precharge Delay(tRAS): 12

Are the numbers above correct?

I am also concerned with the following items in italics.

ACT to ACT Delay(tRRD): 3
Rank Write to READ Delay: 3
Write to Precharge Delay: 6
Refresh to ACT Delay: 42
Read to Precharge Delay: 3

What are these numbers? Do I need to change them? Where would I find the correct values?

If anyone here can help me out I would greatly appreciate it.

If you require further information I will check back here shortly with answers.

Thanks in advance,
Mark.

 

[cfvh600]

Normally the motherboard's auto settings don't set the memory timings to run at their optimal settings.This is to ensure overall system stability.You can change the memory timings to their specifications as indicated above.I don't think the timings you've mentioned in Italics are very important.

 

[apoth99]

I changed the figures, but I am now getting BSOD during Call of Duty 4. The message indicates a memory dump and the computer resets.

Can anyone help explain why?

 

[ivanski]

Check to see if the correct voltage is set for your memory,wich I believe is 2.1
Auto sometimes gives it a lower setting than whats required.

 

[apoth99]

How do I see the voltage for RAM?

 

[skyline0511]

You know how to change the timing but not the Voltage? The DRAM voltage settings should be near in the same section as the timings

 

[jsc]

I am going to be rude and tell you, "RTMF." Then I am going to be polite and help anyway.

According to the copy of the manual for your motherboard that I downloaded: Section 2-7 (page 46) MB Intelligent Tweaker has a menu entry labeld "DDR2 OverVoltage Control". You can adjust your DRAM voltage there. Set it so you are applying 2.1 volts to your memory.

DDR2-800 is equivalent to a 400 MHz FSB. If you are not overclocking past that, your memory should run at 4-4-4-12 timings. But if your system is still unstable, you will need to increase the timings.

How much difference does decreasing the memory timing make? I spent the extra money for DDR2-1000 memory. I wanted plenty of OC headroom. I was running an E6600 at 3.3 GHz (FSB from 266 MHz to 367 MHz - DDR2-733 equivalent). I was able to drop the memory timing from its default of 5-5-5-15-2T to 3-3-3-6-1T.

The good thing was that it gave me about a 6% increase in memory bandwidth. The bad thing was that it was only noticeable in benchmarks.

 

[apoth99]

I knew it had something to do with the DDR2 OverVoltage part. Only it gave the option to only at 0.3v or 0.4 etc. It didn't actually say 2.1v which was what I was after. I realised after further reading that the actual voltage of ram is about 1.8, so adding 0.3 would make it 2.1

The guys at corsair were quite helpful and also got me to change the memory multilplier to 2.5, being 2.5 x 266 = 800.