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Dominator CM2X1024-6400C4D Timings detect incorrectly


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CM2X1024-6400C4D Ram (XMS2-6400 1024MB 800MHz 4-4-4-12 XMS6404v2.2 0645285-32) This is from the label on the Dominator RAM itself.


When used in an EVGA 680i board with BIOS21, the board detects the ram with timings of 5-5-5-18, 1.9V.


Why does the ram not detect as 4-4-4-12 ? Is this a BIOS problem or a Micron/Provos problem or other??


Before playing with overclocking ram, I worked on the E6600 CPU first... getting 3.0GHz with a FSB of 1336 (and an autodetected 789 MHz ram). Everything worked well.


Next I wanted to set the ram to match the Corsair specs 4-4-4-12, 2.1V. Once I did this, the system became unstable. (DOOM3 crashes).


It seems that I can only run the 4-4-4-12 timings if I do NOT overclock the FSB. If I overclock the FSB, then I need to use 5-5-5-18.


Am I doing something wrong? Is my ram not up to spec, or do other users have to manually enter timings to meet spec (so the BIOS autodetect isn't perfect)?

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Autodetect is fine for a stock system. You are playing with overclocking. When you raise your FSB, you are concurrently raising your memory.


You need to set your system to manual and manually enter the memory ratio and timings as well as multiplier.


I would try:


FSB at 350

Cpu Multiplier X 8

RAM at 667Mhz

Vdimm at 2.1v

MCH at +1v

Set your timings to 4 - 4 - 4 - 12.


Test for stability. If stable move to 375 and repeat testing. Then try 400Mhz and repeat testing. 400MHz X 8 = 3.2Ghz and will give your concurrently raised ram an 800MHz speed. Please set down your system specifications here so we can help you with your system and overclock.

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So you're suggesting I "downclock" the RAM and decrease the multiplier?


I am a NEWB to overclocking.... but I am guessing now that when I overclocked my FSB before that my RAM speeds didn't match and that's why I was crashing?


Thanks for taking the time to reply.



(I am using the P23beta BIOS now).

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I am suggesting that you raise your FSB far more highly and keep your ram at a 1:1 level witlh the FSB all the whilst maintaining the lowest (tightest) timings that the ram will make at these settings.


You will then have:


  1. A far higher FSB.
  2. A 1:1 relationship with your FSB and RAM
  3. Timings that are indicative of fast throughput.


If you can make a 400+ FSB with an 8 X multiplier, that will give you 8 X 400 = 3.2GHz and if you set your ram at 1:1 you will be running the ram at 400 X 2 = 800Mhz. Both RAM and FSB will be synchronous.


When you watch a relay race. Both runners are attempting to run synchronously to be able to pass the baton with no loss in speed. The same thing goes with the CPU <--> DATA <--> RAM.


Some people run the RAM faster than the CPU and yes, some canned benchmarks (SuperPi, etc) will show this to be a benefit but in the real world of the system these benchmarks do NOT take into account the PCI Bus, Hard Drive, CD-ROM, Sound Card, etc, etc) and so are not truthfully indicative of the entire system Use a digital stopwatch and load a game such as F.E.A.R. and you will then see that running the RAM at twice the speed of the CPU gives very little (if any) difference.


Given these identical (except for BIOS Settings) systems:


  1. 356Mhz (1424Mhz Quad Pumped) FSB X 9 = ~3.2Ghz with DRAM @ 712Mhz at 4 - 3 - 3 - 10 timings
  2. 400Mhz (1600Mhz Quad Pumped) FSB X 8 = 3.2Ghz with DRAM @ 800Mhz at 4 - 4 - 4 - 12 timings.
  3. 450Mhz (1832Mzh Quad Pumped) FSB X 7 = ~3.2Ghz with DRAM @ 900Mhz at 5 - 5 - 5 - 15 timings
  4. 534Mhz (2136Mhz Quad Pumped) FSB x 6 = ~3.2Ghz with DRAM @ 1066Mhz at 5 - 5 - 5 - 16 with timings


The 4th system would be the fastest by far even though each system is running at ~3.2Ghz. However, getting a system to run with stability at 534MHz is only done by the most extreme methods of cooling the system and the best components. It is however, the pattern and standard to follow to gain the most stable and fastest system.


Your system, if tweaked correctly will fall somewhere in between System #1 and System #4.


Mine is situated between System #2 and System # 3. Keep in mind that when you set your RAM (Linked) to 667 and raise your FSB, you then concurrently raise your RAM. Set your RAM to 667 and your FSB to 400Mhz will give you 800MHz RAM.

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WOW DerekT thanks for the info.


I will do some testing once a final BIOS is released. I am currently running the P23beta. Not bad but a few unusual things still going on.


System seems pretty stable for Internet, Office stuff... but it has frozen the last two cold boots... I then had to hit RESET.... which meant that XP ran CHKDSK the next boot.

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