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need help with TWIN2X2048-8500C5D

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ver 4.1 volted at 2.1


I have a rock solid stabile 3.6 ghz with corsair twin 6400 800mhz. I recenlty got two new 8500 dominators direct from corsair. I put in the bios 5-5-5-15 2t with the memory set at 2.1 volts and 1066 speed.


The system is not stabile and when I back it off to 800 mhz, it runs ok. I keep getting freezes in Vista. Nothing else has changed and like I said, it was rock stabile with the 800 mhz sticks.


Can you help me? What do I need to run to check the memory?


Can I volt this differently? 2.2 or 2.3 volts on a 780i motherboard?

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If you are running ANY type of Intel or 680/780i chipset DDR2 motherboard with 2x2GB for 4GB or 4x2GB for 8GB of ram, tRFC will have a major impact on how your system will run. There seems to be issues with low tRFC at Auto and these boards have no ability to set tRFC.


What does Auto show for tRFC?


Download Memset Here

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I forgot that I don't have that memory installed as I needed the system stable for a little bit. I have the corsair 6400 in. I know it's a bone head thing, but I asked this question hours ago. Sorry.


What should the values be? I don't have a trfc.


I have











Which one are you referring to?

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yes I do. I just figured out that corsair sent me 2 - 1 gb sticks but put them in a package that said 2x2048-8500c5d. I didn't even think about it when I made the post. I just copied the numbers without thinking. I am sorry, I truly didn't realize it.


It's straight from corsairs RMA department. I must appear pretty stupid at this point. Don't know what memset is...got the wrong number down.....go ahead.....

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Download memtest from--->
and extract the ISO image. Burn the ISO image to an CD-ROM disk.

Enter your BIOS. Load Setup Defaults. Save Setup Defaults. Remove the CPU overclock for testing purposes. Set to the below values.


**System Clocks**

CPU Freq. MHz = 266

CPU Muliplier = 9

PCIe x16, 3, MHz = 100

SPP<->MCP Ref Clock, MHz = 100

**HT Multiplier**

nForce SPP --> nForce MCP = 5x

nForce SPP <-- nForce MCP = 5x


**FSB & Memory Config**

SLI-Ready Memory = Disable

FSB - Memory Clock Mode = UnLinked

FSB (QDR), MHz = 1066

MEM (DDR), MHz = 1066Mhz


**Memory Timing Section**

Memory Timing Section = Expert

tCL = 5

tRCD = 5

tRP = 5

tRAS = 15

Command Per Clock = 2T


* Advanced Memory Settings**

tRRD = Auto

tRC = Auto

tWR = Auto

tREF = Auto

**CPU Configuration**

Limit CPUID MaxVal = Disabled

Intel Speedstep = Enabled

CPU Thermal Control = Enabled

C1E Enhanced Halt State = Enabled

Execute Disabled Bit = Enabled

Virtualization Technology = Enabled


CPU Core 0 = Enabled

CPU Core 1 = Enabled

CPU Core 2 = Enabled

CPU Core 3 = Enabled

**System Voltages**

CPU Core = Auto

CPU FSB = Auto

Memory = 2.1v

nForce SPP = 1.2v

nForce MCP = 1.4v

HT nForce SPP <-> MCP = Auto


After setting to these values, save them and boot to the Memtest ISO. Allow for two full passes.



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I made two passes with each stick and both passed.


Here are the values in the bios

5-5-5-15 2t

speed 1066

volts 2.1

trrd 4

trc 31

twtr 10

tref 7.8


It starts to boot into windows at 1066 and restarts


edit. I changed the trc to 26 and it is booting into windows. Can you explain what this value should be? I saw to change it on another forum.

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Can you explain what this value should be? I saw to change it on another forum.


tRC is the random access cycle time, sometimes called the bank cycle time. This basically means the number of clock cycles (ticks) required to open and close a bank of DRAM. The DRAM bank must be refreshed with an electrical chage and that refresh allows the data held by the bank to continue it's ability to be read. If the refresh does not occur in time, the data (for lack of a more easily understood term) fades away. Remember, these are electronic capacitors and electronic capacitors are, (by the very nature of their design) leaky. If the time required to open and close a bank is too short, there is a "tRAS violation". You can read this as "Blue Screen". tRAS is the minimum number of clock ticks required to access a row of data in DRAM between the data request and the precharge (tRP) commands. Too low a tRAS is very dangerous to the stability of the OS. It leads to data corruption on the hard drive and often if you have been effected by tRAS violations, then you would do well to perform a fresh install of the OS.


What is your Auto SPD set tRC? Download CPU-z and look at your SPD settings. What is the tRC?

Download CPU-z from

Please post screenshots of your CPU-z CPU/Memory and SPD tabs.


The general rule of thumb is tRC = tRP + tRAS





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This is at 800 mhz. I could not get 1066 to successfully post and stay stabile.

When it is set at 1066, the auto in the bios for trc goes to 31. I posted earlier that 26 booted then after the next reboot it didn't stay stabile. I can try again in the morning. What would your recommend I set it at? 20?


Sorry for the double post.

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I just so happens I have one for emergency. What would you like me to do?


Just an install of the OS on the new drive. This will serve to isolate the Hard Drive from your issues. What we need to do is find the issue, by removing what isn't the issue. We will be left with what must be the issue that way.

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